"Gay Much" is used in everyday conversations to state that somebody is acting very 'gay'. It is also to suggest that one (persumably a male) likes to become aroused around other guys. Often can be used in threatening situations where a person find themselves proned to attack from say a rapist or cock hunter.
1. You are with a group of mates and suddenly you see a male checking out another male, you then say gay much.
2. A gay man starts wandering towards you, he then says come here little boy. You then say 'Gay Much', this will in turn cause the attacker to become confused and weak, he will start foaming around the mouth, then will collapse on the ground and die.
A nickname to suggest one (a male) is very into having sexuall thoughts about other men. Can also be used to say that a certain male has a fetish for one particular name, and will tend to have sex with people with this name.
You think one has gay thoughts about men, you then call them "Tomo".
If one tends to spade and have sex with girls only the same name. For example 'Hannah', then you call them "Tomo".