Red flag, likely no. Why?
1) he's likely a butt guy, or watched too much porn.
Hence he feels excited doing so.
2) he may believe that the "pain" he implanted on your butt is actually subtle "pleasures".
Ya, many guys believe it because of porn and or articles that discusses spanking.
3) he probably enjoys spanking you. Its a fetish in many guys.
Conclusion: as many wrote, if you don't like, just tell him. Chances that its a red flag in your relationship is very low. I fact, its more of a sensual one, at least to him.
I think it depends how the sex was going, was it slow and passionate and fastish and quite naughty, I'm guessing you were on top or in doggy position for him to have access to slap your ass.
I figure if it was very heated and naughty fast riding or sex position you were in he prob thought yiu were a bit naughty and thought you'd like the spank.
If it was slow and passionate then seems a bit weird to do it
Scroll Down to Read Other Opinions
What's Your Opinion? Sign Up Now!I THINK it's more like A red ass cheek not a red flag
It means he really likes you. If he does it too hard just tell him to squeeze your butt instead of slap it.
Does it? 😂😂 wait really?
Is that how guys show that they really like you? They slap you on the ass? 😂😂😂
he's just trying to excite you. He was probably taking a shot in the dark if it was the first time it happened; but if he does anything you find questionable... Just tell him what to do; don't stop him (unless its something injurious), just tell him what would feel good because he wants to make you feel good.
I sure hope not!
Guys in porn slap butts all the time and probably where he got the idea. If you don't like it just tell him. A decent guy will respect your wishes.
If i was having sex with a girl for the first time i would not be slapping her butt the first time
No, he was just having a bit of spontaneous fun.
Nope, I have and will continue if the opportunity arises
Guys see that on porn, so he thought you probably liked it.
Just tell him how you feel.
This question is a red flag
How?
By expecting. Most people like to be surprised. You have 15% red flag approval. Get out of your head and be present or mindful. It makes surprises enjoyable
Lol if you can have sex with him then why does a slap on your butt matter so much?
No not at all.
He just had a fetish for that sort of thing.
Ask him if he wants to eat you ass next time
Sexual Relationships 
Sexual Health 
AI Bot Choice
Superb Opinion