Full transparency: "Embarrassed" is a relative term here. Maybe a better way to describe this would be, "things that momentarily give us pause but then we're like, 'lol, nah we're having sex.'" That's more accurate, but it makes for a longer headline.
1. How dirty his room is.
This is the kind of thing that creeps up on you while someone else is in your room. Things you missed ... the layer of dust and dirt all over everything, clothes piled in the corner, a fast food wrapper ... suddenly become so obvious. It's like seeing the world with fresh eyes. And he's realizing that as he's humping away at you. For some guys, the best sex position is less about what's going to feel good and more about what's going to keep you from getting a glimpse underneath his bed.
2. The fact that he hasn't washed his sheets in a while.
Do they smell like sweat, or butt ... or is that distinct odor butt sweat? Can you smell it? They say that if you want to last longer in bed, a guy should think about baseball. But he can probably last longer just trying to remember how many months it's been since he washed his sheets.
3. His O-face.
It feels like we're making a face like we bit into a lemon that's also sucking the life force out of us. So we can't imagine what it looks like, and it's probably best we don't want to know. Seeing your own O-face is probably some Ark of the Covenant-level shit.
4. Condoms ... condoms everywhere.
What is the appropriate number of condoms for someone to have in their bedside table? Is there such a thing as too many or too little? Is it better to have an open box (implying they've been used before) or a new box (implying he bought them because he assumed he was having sex with you)? Maybe he's just better off leaving the room and coming back with one. It's probably less embarrassing for you to just assume he keeps them in his kitchen or something.
5. His awkwardly positioned mirror.
DON'T LOOK AT IT DURING DOGGY-STYLE OR YOU WILL SEE DIRECTLY UP HIS BUTT HOLE.
6. How long — or, uh, not long — he's lasting.
There's a window here that's acceptable, and that window is essentially "anything before you come is bad, but anything, like, 20 minutes after you can't come anymore is also bad."
7. The fact that he hasn't been taking advantage of his gym membership.
His pre-kid dad bod might not be so bad when he's just seeing it in the mirror brushing his teeth. But suddenly, in the light from his single lamp in his dorm room, he might doubt just how good he looks. He might start regretting all those times he took a nap instead of going to the gym.
8. His balls.
I don't care if he's got the best-looking, most photogenic dick in the world ... his balls probably look weird. Because they're balls. We need more balls acceptance in society, honestly.
9. The fact that he lives in what basically looks like a prison because he has no sense of style.
Some guys are really, really good at decorating. Some guys live like they're on the run from the law and might need to flee in the middle of the night at a moment's notice.
10. Evidence of some weird hobby.
Listen, I don't want to shame anyone here. But some hobbies are probably best left for a few months after dating. Maybe he left out all his model planes or hundreds of classic video games or anime wall scrolls. He loves these things, and likely you will come to accept them someday too, but there is such a thing as too soon. Also, staring at a Spider-Man action figure while you bang is kind of a boner-killer.