Yes it is cheating. Participating means sucking his penis, basically. A light touch or brief hold of his penis is as far as it can go, I would say, before it becomes cheating. To those who say it's just a party and it should be fun; yes it should be fun and yes the whole theme is based on sex... but I am sure you girls would flip out if your man had a woman sucking his penis at a party, or if he himself went and did a strip show for women and they sucked his penis. Come on! The same girls who say all this then demand fidelity! One last night? It's often not just the hen who does it. When there is sucking, it often graduates to intercourse, btw. And comparing this to some guy getting a frustrating lap dance is absurd. I love women, but by the gods, the sexes are so unequal!
Oh, I forgot one important thing: some girls actually kiss the stripper. To me, sucking would be bad enough, intercourse likely a deal breaker, kissing would be crushing combined with sucking and bad enough on it's own.