Sex is okay to have once you are a sensible age because even wearing protection you can still have a baby.
If you have ever had sex, not oral sex, but SEX, than you are not a virgin. If you haven't had sex, then you are. And that's how you know.
Honnestly i dont know how to have Noughty sex :(
have sex
Just go look up " How do you have sex " and you will know.
Very few anime's have sex in them, but there is one that i know has sex in it, Yosuga no Sora
Sex-linked traits
you will know when they are playing for sex because you can sometimes see it in their eyes. if not....you can tell becausee they are kind of acting strange or they are like flirting in a way. you have to have the right instincts to know if they are playing for sex.
the same ways you know if the opposite sex likes you. human nature doesn't change.
naturally people still retain sex drives later in life and and there is nothing wrong with consensual sex even with someone you do not know.
You can give him oral sex and let him know you are enjoying it.
get a test
when the only times they want to have any form of communication from you is to have sex, or talk about sex