From my dating experience, most guys have something they are a little shy about that really turns them on. My ex used to love when I fingered his ass while I blew him, and I dated another guy who loved having his nipples licked, sucked and bit.

However the one I still don't understand was I started dating this older gentleman and he just loved to cum in my hair. More, than blowjobs, sex, he wanted me on my knees in front of him while he jerked off and came on my head. Sometimes he'd want me to lick his balls while he jerked but most of the time he was content just to shoot all over my hair. It didn't bother me to much and it made him happy but still was a weird experience not going to lie!