When your girlfriend (or wife, or whomever) stuffs her panties in your mouth so that only the tag is hanging out, leaving you looking like a Hershey's Kiss.
When a man is having anal sex with his partner and pulls out his penis, if there is a little piece of shit on the head of his penis that's a Hershey's Kiss.
I pulled my dick out of her ass and flicked off a Hershey's Kiss; she then blew me.
Upon completing a rimjob, and finding your partner has ill-prepared their anus for such coitus, vengefully kissing them to show your displeasure in the fecal matter that has accumulated on your lips.
"He kept asking for a rimjob and assured me that he kept his ass clean as a whistle. Sure enough, he was a liar like all the rest, and I had to give him a Hershey's Kiss to show him how it felt!"
The poop stain left on your underwear after a wet fart. Can also mean the piece of poop itself.
After eating the beef and bean burritos, little Billy was upset that there was a Hershey's Kiss left on his tighty whities from the huge, wet fart he ripped.