Responses
http://www.mangago.zone/read-manga/simplified_pervert_romance/?w4ZU
Not really sure if this counts bc he only slapped it after sex but the uke is into pain so more ass slapping may be included??
...
Anyway here is the prequel in case you are interested :
http://www.mangago.zone/read-manga/rational_pervert_romance/
Bl recommendations where the seme slaps the ukes butt or grabs it while doing it