Kevin wakes up disorientated and hung over with an arse that feels on fire.
Looking around carefully as he rubs the sleep from his eyes he realises that he is in Esposito's bed, naked together with Esposito.
He shakes his partner awake. "my arse hurts" he complains as he reaches for a kiss.
Esposito smiles at him and says "well you're the one who wanted it". Annoyed Kevin hits him with the pillow and tells him to shut up.
The alarm beeps again reminding them it's time to get up. Wincing Kevin gets up out of bed and slowly heads towards the bathroom.
Esposito's eyes gaze at his arse as he goes. Kevin smirks and asks him if he's enjoying the view. Esposito reluctantly gets up and joins him in the bathroom where Kevin is shaving.
Carefully embracing the smaller male Esposito takes a better look at the tattoo sitting on his partner's rump.
The skin around the tat is red and raw but he has to admit that the tattoo looks great. The long flowing letters curling around the flesh marking Kevin as his.
Kevin catches him looking and pulls him into another quick kiss. Esposito moans into the kiss as Kevin's hands start wandering again.
Esposito stops him grabbing his hands.
"Not again" he grumbles "my arse is still painful from last night".
-Bonus ficlet-
Castle catches them together late one night in the break room. Even though its dark and they have their backs pressed up against the coffee machine Castles can tell that they're kissing. Javier's hands are fondling Ryan's butt and even though they're all the way across the room Castle can feel the heat between them.
As he watches things slowly start heating up, hands exploring further going lower as their kisses became needier and he decides to make himself scarce just in case they notice and decide to kill him for exposing their secret.
Castle finds himself oddly jealous. Not of that he finds himself saying to Alexis later, God if anything he tells that girl too much, but of how much progress the two of them have made compared to him and Beckett.