When I was younger I refused to kiss a girl after she had my dick in her mouth. I got over that. First time a girl kissed me after she swallowed my load a thought I was going to puke. I got over that. Seeing how the girls LOVED it was hot.
Many girls asked me to go down after we fucked. First time was about the same, thoughts of ....... I learned to have her wipe off then I was OK with it.
Years later (present day) wife and I get into mfm fun with a guy we know. Him or I have no problem kissing her after she's swallowed but not right after. Going down on her after she wipes off is good, doesn't matter if it's his or my load or both. We wipe her off and go at it.
It's fun because she gets off and that makes it fun.