LavenderAuthor
(Crossposted from AO3)
Imagine that in the middle of sex, both feeling good, Stiles opens his mouth and before Derek could say anything cocky(heh) about how good it feels, he just blurts out "Are we still going to the grocery store later? Erica has been whining about someone eating her ice cream and it's nearly that time of the month."
Derek may feel self conscious the first time like "Am I not good enough at this? I thought he was feeling good." but after a while, he's just used to it to the point that he chimes in and then they have after sex cuddles discussing whatever Stiles has on his mind for later that day.