Look at this S! Cupid's Prank - Vol. 2 Ch. 13 - The Birthmark's Limit

[MangaDex]

 

[PuddenJelly]

DaMn that's tuff

 

[thegodkiller]

yeah he just punched me in the eye teehee

 

[etriuswimbleton]

Gotta give some props though. he actually did some trial and error. I very much expected he would only know one flaw and that is when he pulls out, the magic disappears but he actually tested it again with a condom. Bro out here doing hypothetical testing.

Wait...did he cum inside Takako?! isnt that gonna be a problem!? also wonder if they retain some memories during the influence of the magic