It means, she is ready to fuck you if you believe her.
Used especially while you're referring to your female friend in your conversation, though it can be used by females for males. *his/her pants off* is used as an adverb in this sentence. It means, she is ready to fuck you if you believe her.
Person1: Hey mane! I heard that you were hitting on her. Is it true?
Person2: Nay, she is just trying to convince you her pants off! (convince someone your pants off)
A person who doesn't consider themselves bisexual or bi-curious, but entertains the thought of a same-sex experience with the right person under the right circumstances.
If there are two 'friends' who have a friendship but only one of them puts effort into this friendship while the other one only puts in effort when its convenient for them. Therefore turning this friendship into a convienceship.
Cory is always trying to hang out with Niki, but Niki only wants to hang out when its convenient for her. I guess they are in a convienceship now.