It's an bro/sis (or cousin) incest hentai oneshot. The sister works at a cafe and she jizzed into her brother's drink/desert and he ate it.

I think it was scanlated by one of the main hentai groups (SaHa, maybe). I don't know, but I've searched and can't find. ):

I know you're all thinking "wtf?" but don't ask questions. >o

Gimme name now.

EDIT: ew, typo in title. ;/ *identify
change mod plz? kthx