What is this 'basic concept of sexuality' as you understand it?
That, as I've stated previously in this same thread, sexual orientation is ingrained and unchanging, not based on actions. People seem to be stating their personal opinions as fact.
"Yeah, that doesn't work for me. If a guy is sucking dick, taking it up the ass, etc., his heterosexual membership card has long been revoked. He doesn't get to be "straight" any more."
Quotes like that are exactly what I'm talking about. A straight man can be tickled by, tied up by, even engage in sex with another man and it doesn't make him homosexual. There are thousand and thousands of people who have experimented, including my lesbian friend who decided to fuck guys until she made herself straight. Guess what? It didn't work, because she's a lesbian and always was a lesbian even when engaged in sex with men.
Acts of a sexual nature do not determine sexual orientation, you can't fuck a girl one night and be straight and fuck a guy the next night and you're gay. It's not how it works, despite folks opinions on this thread which really don't mater in the firt place, because you can't debate fact.