Here's another thought. I'm sure you've heard the question... "Why do dogs lick themselves?" Of course the answer is always "Because they can". You've probably also hear people say that if men could blow themselves they'd probably never leave the house. To me, if this is just a fantasy, what you're describing kinda fits in there. Haha. Work on your flexibility and your problem is solved!

On the other hand, if you're saying you want to actually have a real life "suck buddy", well then it makes sense that you probably are at least bisexual. But, this kind of situation would probably be REALLY hard to find in the safe, trusting way you want without extra baggage you don't want.