I always was a quiet guy, but given a comfortable setting and the right audience I could make people laugh. I've been watching a lot of comedy and cabaret and that helped me hone my skills. Never liked cracking preset jokes, but I learned how to play with language, use irony properly and to adapt to each situation. At some point I wanted to turn this into my profession, but I never had the guts. I'm only comfortable with a group up to four people and could never act on a stage...so I keep it to myself. Total lack of confidence in any public setting.
But when you have some eloquence and wit you certainly are more flexible - therefore it becomes easier. A lot of people seem to be more receptive to situational humor.
So you don't have to wait for the right moment - every moment can be the right one. Never waste an opportunity to make someone laugh.