I am looking for a specific fic I read a while back and have been looking for for weeks now. I can't seem to find it anywhere and hoped one of you lovely people may know which one I am referring to. Here is what I remember...

Sam and Dean are wrestling around or something (I believe on a couch)
Dean decides to spank him? maybe?
Sam likes the spanking (or gets turned on by the wrestling)..a little too much
Dean figures out little bro likes it and it leads to fingering and maybe full on sex?
I think I remember something along the lines of "oh my god you actually like this" or "are you getting off on this?" from Dean
and I am almost certain Sammy is underage at least (maybe 14 or 15)

Any help locating this would be greatly appreciated, it totally filled all my kinks!