It starts as an accident. They’ve had a few too many beers while quietly commiserating over the loss of a midshipman on their watch. They both fall asleep on Gibbs’ too small couch and in the night they shift around until they’re both on the carpet in front of it entwined. When they wake they both just shrug and go about contributing to the anti-hangover routine as they have many times in the past.

The second time it happens is more of a choice. They’re stuck a few hours outside of DC in a sudden blizzard. They manage to make it to a motel to find there are only two rooms available, one with two doubles and one with a Queen. There are no cots available and Tony offers to take the couch in the Queen. Ziva agrees to share the other room with McGee and all seems settled. Until they arrive upstairs and find it’s a loveseat not a proper sofa. Tony glares at it balefully for a moment before Gibbs growls “Come to bed DiNozzo.” Again they go to sleep on opposite sides and wake wrapped around one another, Tony’s head tucked neatly into Gibbs’ neck. Tony just can’t let it pass a second time, “Sure is warm being curled up with you Boss. I could stay all winter.”
Gibbs laughs but doesn‘t comment. They languish a few moments more before Gibbs gets up to take a shower and head down the hall to check on the others.

The third time it’s deliberate. A young marine who had turned to Tony for guidance after receiving the news of his father’s death killed himself. Tony’s a wreck, blaming himself obviously. Gibbs sends the others home immediately after a distraught Tony leaves the building and follows his second in command home. As he’d expected when he lets himself into Tony’s apartment the younger man is already halfway through a tumbler of single malt. Gibbs makes no move to prevent him from finishing the drink but silently puts the decanter back into the liquor cabinet and locks it. Tony puts the empty glass down with more force than is strictly necessary, “Going to claim it isn’t my fault? That he would have killed himself no matter what?”
“There’s no way to know what he would have done. But there wasn’t anything you could have done Tony. Now come on, I’m putting you to bed.”
“Too cold and quiet to sleep,” Tony protests almost silently.
Man of actions more than words Gibbs merely pulls Tony into the bedroom, strips them both to their boxer and slides into bed with Tony, holding him as an exhausted sleep takes over.

After that it becomes something of a habit, when one or the other of them has a bad day they mention that it’s cold or will be cold and the other turns up on their doorstep after work. Tony occasionally stretches the definition of a bad day but as they both sleep better together Gibbs leaves it un-remarked. After four months they’re spending at least two nights a week together and each has clothes at the other’s place. Which is how Abby discovers the situation.
The team raids the hideout of a terrorist cell only to find it booby trapped. Tony manages to get the rest of the team clear of the blast but ends up with a four inch gash along the line of his temple. Despite the lack of a concussion the doctor insists (after examining Tony‘s file) on at least two days in the hospital and Abby volunteers to pack Tony a bag.
It’s not the first time she’s packed him a bag, so she notices the sudden order in his drawers, or at least the top two of them. But the clue that gives her the why portion of the equation is when she opens the closet and finds blazers and pants Tony would class as coming from Sears. Her initial reaction is to squeal in delight, but as she continues packing she becomes increasingly put out.

When she arrives back at the hospital she strides into Tony’s room with purpose and closes the door firmly before so much as looking at him. “You’ve been holding out on me. Why didn’t you tell me you’re getting it on with the Bossman?”
“What?!” Tony splutters at both the accusation and the suddenness of its delivery.
“Oh come on Tony, he’s got underwear in your drawers.”
Tony shakes his head and immediately regrets it. “We’re not having sex Abbs. We just… sleep together sometimes.”
“You didn’t hit your head that hard Tony.”
“When I say sleep I mean sleep.” He blushes deeply at her skeptical look. “It’s about human contact. At least for me it is.”
“I get why you’d want to cuddle up to him. If the hugs are anything to go by he’s got to be one hell of a cuddler. What I don’t get is how you’re cuddling with someone you’re so obviously in love with and not having sex.”

“I am not- What makes you think I’m in love with him?”
“Tony, you eye him like a lion in the zoo eyes the gazelles. And it’s not the way you look at a pretty girl. It’s not just physical attraction, it’s longing.”
“I- It- Longing Abbs?”
“If I had to be more specific I’d say you look at him like if he would just look back at you then your whole world would be exactly as you want it. What I really don’t get though is why you think he isn’t looking right back.”
Tony sighs, giving up, “Because he isn’t Abbs. We’re talking about a man who has no hang ups what-so-ever about taking what he sees as his. And aside from manhandling my mostly unresponsive ass into a bed to sleep off a depressive funk he’s never really touched me. When we sleep together I’m the one who moves to him in the night. The second I start to move he takes his hands off me and lets me go on my way.”
“If you weren’t in a hospital bed I’d smack you upside the head.”

“That’s my job.”
“And I’ll leave you to it,” Abby announces kissing Gibbs’ cheek before retreating.
“What’s she going to smack you for?”
“She found the clothes you keep at my place.”
Gibbs chuckles, “Jealousy or annoyance at having been left out of the loop?”
“Mostly the latter.”
“’Bout time she knew.”
“Why?”
“She’s a good ally when you’re looking to keep a secret.”
“Thought we were doing just fine.”
“Not much of a secret so far.”

“Don’t think Vance would care that all we do is sleep Boss.”
“My point exactly.”
Tony watches Gibbs for a minute or two before responding, “I was hit in the head with flying debris today Boss so I may be inferring things you aren’t implying. Wanna run that by me again?”
“This clear enough for you Tony?” Gibbs leans down and kisses Tony, nothing drawn out, or particularly intense, just a swift, warm ‘hello’ sort of kiss.
“Yes and No. Obviously you just kissed me but I did hit my head…”
“Guess I’ll have to do it again after I take you home.”
“Home? As in back to your place?”
“That is the plan. Told the doctor I’d look after you and she said you could come home in the morning.” He runs a gentle thumb over the bandage. “Been waiting for you to make up your mind. Guess watching you go down reminded me what a hard head you’ve got.”
“We’ll talk tomorrow then,” Tony murmurs as sleep over takes him.

Gibbs doesn’t hold Tony’s hand, or even stay all night, but when Tony awakens he’s there. “So I wasn’t hallucinating.”
“I did tell you.”
“Doc still gonna let you spring me?”
“If you’re still coming home with me.”
“We gonna talk when we get there?”
“If you‘re lucid enough.”
“Let’s go.”

Neither of them says a word in the car. Or the drug store. Or as Gibbs pushes Tony firmly upstairs and into the bedroom.
Finally when he’s settled Tony can’t take it anymore. “You said you were waiting for me to make up my mind, but I’m not a mind reader Boss. I had no idea you were offering anything other than a good cuddle.”
“You’re brighter than that Tony.”
“And you really are a bastard for trying to put all this on me.”
“Every damn time it happened I pulled you close and pet your hair Tony,” Gibbs’ growl is somewhere between annoyed and amused.
Tony flushes, “I, um, I didn’t know that. Generally I was asleep as soon as my head hit the pillow. And I figured I was the one initiating the cuddling actually.”
Gibbs shakes his head, “Guess I’ll just have to make sure you’re awake when I do it tonight then.”

The first time someone catches them it’s an accident. A cell phone starts ringing in the middle of the night and Tony reaches for it blindly, managing through long year of practice not to sound half asleep as he announces “DiNozzo” into the phone.
McGee’s unmanly squeak of “Tony?” causes him to actually wake up and look at the phone.
It takes about twenty seconds of eye contact for Gibbs to assess the situation and take the phone out of Tony’s unresponsive fingers, “What’d you need McGee?”
After a full minute of silence McGee manages to get himself together enough to answer, “Metro just called in a hit on the bolo for Mark Fells’ corvette.”
“Where?”
“Little cup of sunshine diner in Maclean.”
“We’ll meet you there in twenty.”

The second time it happens is more of a choice. Tony’s been putting Abby off about movie night for almost a month. He’s done it skillfully enough that she doesn’t seem to realize it but he’s beginning to miss her. Gibbs takes one look at him eyeing his phone and swoops in for a kiss, “Invite her over to watch Memphis Belle. I’ll get the hot air popper out of the attic and make real popcorn. If she doesn’t deafen us both with her squeals of delight and outrage it’ll be fun.”
Tony’s smile at that could light the city streets for a month.
The only thing that outshines it is the smug gleam in Abby’s eyes when she coerces Gibbs to sit in the middle so she can get a little cuddling in too without “Encroaching on Tony’s claim.”

The third time it’s deliberate. Gibbs invites Jackson down for memorial day weekend while they’re having their morning coffee. Tony resists the urge to comment, knowing he’ll get the information he needs when Gibbs decides to give it. Sure enough after less than three minutes there’s a tap under his chin, “It’s time he knows.”
“And if he takes it badly?”
“His loss.”
Three weeks later Tony looks lost when Jackson hugs him and chuckles, “About damn time.”

After that it just seems to happen on it’s own. Ducky notices that Tony’s DVD collection has migrated to Gibbs’ house. Fornell walks in on Tony cooking dinner. Ziva notices that they always drive in together. The girls in HR read Tony’s change of address. Which is how Vance finds out.

The explosion is somewhat smaller than Gibbs expected honestly. Vance just walks to the railing and shouts “Gibbs my office. Now!”
He answers the summons but grins unconcerned, “Something bothering you Leon?”
“Did you honestly think no one would notice?”
“Notice?” The innocence is patently fake, but worth a try.
“I don’t care that you’re screwing DiNozzo, Gibbs. But moving him into your house was stupid. Now I have to separate you.”
“As far as you know I’m renting him a room.”
Vance eyes him for a long moment before nodding, “Fine but if I get one complaint. Hell if I get one official inquiry you’ll both be investigation the migration habits of Alaskan Salmon faster than you can say discretion. Do I make myself clear?”
“Crystal sir.”
That night when Gibbs pulls a lightly dozing Tony close and earns contented murmur he knows as long as he has this, all is right with the world.