A = Aftercare (what they're like after sex)
Depending on where both of you had sex, Erwin is pretty basic with aftercare. Cleaning you, and cuddle you before going to sleep if it happens in the bedroom. Otherwise, he would quickly help you to get clean, steal some kisses before getting back to work.
B = Body part (their favorite body part of theirs and also their partner's)
His favorite part of you is your fingers. You are able to make him feel good with them, not only in the sexual way but with massages or just some simple touch make him feel light. On him, it would be his nose. Only because you find it cute and told him back in the days you both were flirting that his nose was cute, since that day he kinda like it more than before.
C = Cum (anything to do with cum, basically)
Erwin mostly prefers to cum inside of you to do not make a mess. On the opposite, he really loves making a mess with your cum. So, thigh riding without any underwear is his fav thing.
D = Dirty secret (pretty self explanatory, a dirty secret of theirs)
Late night in his office, when Erwin misses you so badly, his mind can't focus anymore on the work, but just on the replaying memories of your pretty moans, and praise you gave him on the last love-making session. So obviously he got everything in one drawer of his desk to get himself done on this feeling and possibly finish his work.
E = Experience (how experienced are they? do they know what they're doing?)
I'm siding with people saying he's a virgin. I'm sorry if you do not agree with it, but Erwin is so driven by his goal and only that, that he probably doesn't have the time to flirt. If you end up together, you mostly had done the whole job and he just like fall for you and appreciate the effort you've made to be part of his life. So you end up making him progress in sex (even if you are a virgin, you just learn together your bodies and how to pleasure yourself and each other)
F = Favorite position (this goes without saying)
Missionary. He can hold you as close as possible and see every facial expression, he loves it and loves forcing the eye contact when you cum. He feels powerful in this position because you seem small under him (even if you are more muscular than him or taller, this bitch still see you as his little baby no matter what)
G = Goofy (are they more serious in the moment? Are they humorous? etc.)
It wouldn't happen on purpose, He takes sex very seriously. If you happen to laugh it would probably because he had said something that he thought was hot but wasn't, or because it was job-related and you have to teach him a lesson about thinking about work while fucking you.
H = Hair (how well groomed are they? Does the carpet match the drapes? etc.)
As much as he takes care to shave every day to appear "more professional" and how much effort he put on his hairstyle to be neat, I would bet that he take care down there too.
I = Intimacy (how are they during the moment? the romantic aspect)
Being close to you is his favorite thing. Erwin loves feeling your skin against his. Holding hands, stolen kisses. Those moments are yours, the world doesn't exist during them. You both are just you and not the good little soldiers that try to save humanity.
J = Jack off (masturbation headcanon)
He has no shame doing it. But his sexual need has improved since you two are together. Before he didn't need that much of alone time. But now he happens that some dirty memories can trouble his late work.
