Bring your date to a party and introduce him as "my boyfriend" (or her as "my girlfriend," if you are a lesbian). Or, leave a tasteful gay photobook on your coffee table, or a copy of The Advocate.
you are just going to have to tell her,you guys are young she wont know if you dont tell her
friends
By telling her that you met some one.
you tell a blabber mouth
You ask a friend to tell him for you :)
talk about the person's bad points or have evidential proof that the person is cheating on them such as pictures or videos on youtube.
You could drop small hints, or have a friend (THAT YOU TRUST) ask if he likes you (an tell your friend to say nothing else)
There is no physical way to tell.
To trick the cyclopes into telling the others that "nobody" has tricked him.
try writing a letter
I cant tell you this without you telling me the speed that you are travelling at.
you can tell them anything without having to worry about them telling anybody what was said.