What if its for the sole purpose of self pleasure?

No that does not make your gay. Plenty of straight couples enjoy anal intercourse. Its just a different way to get pleasure, liking it does not make you gay.

Just make sure your using things made for anal foreplay. You don't want an embarrassing trip to the ER because you got something stuck up your rear.

Lots of straight males enjoy anal pleasure and it doesn't make you gay. It can give a heightened orgasm when you masturbate. Just make sure you are using objects that are thoroughly cleaned beforehand as well as afterward if using in the future. Also make sure you don't get anything stuck up there. Just remember the Scrubs episode when the guy gets the light bulb stuck up there.