kiss-blocker

A big shitty cold sore, that takes away ones kiss-ability for two weeks, in effect preventing you from going out, or from picking up a girl (or guy) during that time.

That kiss-blocker on her mouth looks horrible. She won't be making out tonight.

Jackass had just sorted his pickup-lines, when he noticed Melanie's kiss-blocker.
Without missing a beat, he eyed up Melanie's cute ass friend.