"On the subject of Yaoi sex . . . well, think of what you'd like to do to one boy (lick his collarbone, kiss him, blah blah blah), then have the other boy do this to the first boy. That would be foreplay.
Now, the mechanics of gay sex are, to say the least, rather ::cough:: interesting. Basically, Boy A puts a lubricant (slippery stuff) on his "twinkie". Then he sticks said twinkie into Boy B's anus. Boy A should not attempt this without lubricant, because that would cause Boy B a great deal of pain. Big turnoff, unless Boy B happens to be a masochist (someone who is turned on by being abused). Now, of course Boy A with enjoy himself (an anus is a hole too), but how does Boy B get off on this? A little thing called a prostate gland. Nestled someplace against the wall of the rectum, this gland, when pressed, gives great pleasure to Boy B. Pleasure which may, if maintained, cause Boy B to ejaculate. There you go, simplified yaoi.
^_~
Hope that helped,
Siara"