The term "full homo" was coined in response the use of "no homo" by supposed heterosexuals when saying something that may be interpreted as gay. "Full homo" is to be used as a means to convey that what you have said had every intention of being gay and should be interpreted as such.
"I'm so hungry, I would eat a dick. Full homo."
A phrase used in situations when someone of the same sex has done something which has lead to you admiring them on a level beyond the normal level of feelings between two heterosexual people of the same gender. This phrase is for use in rare circumstances when you are overwhelmed by the other persons actions that you feel a level of admiration near to the level felt by a homosexual towards someone of the same gender.
It originates from the phrase "no homo" but is an extreme version of the phrase, only for use in extreme circumstances.
Cindy :o!! You got me a date with the hot guy from marketing at you work place?? I love you babe full homo!!