I have friends, both gay and straight, who have differing definitions of what sex is. [insert obligatory Bill Clinton joke here] Some say sex is anal or vaginal penetration, period. Some say it also includes fellatio, but not mutual masturbation. Some say it’s whenever they achieve orgasm, regardless of the means. Some say it’s whenever you get naked with someone, roll around and kiss, whether you achieve climax or not.
By some of these definitions, I know people who have been sexually active for years (meaning kissing, mutual masturbation, cunnilingus, analingus, and/or fellatio, which they call “just fooling around”) yet describe themselves as virgins or as “only had sex with X number of people” because there was no anal or vaginal penetration.
So, really - what is sex?
Just to get the obvious out of the way (from www.merriam-webster.com - I underlined the important bits):
Even the dictionary allows that sex means both penetration and activities other than penetration.