Throw some potting soil on the ground and while having coitus in the doggy style position with your partner they pretend to be gardening. When finished sprinkle some dirt on their bootyhole and place a seed in the dirt, then plunge the seed in with your thumb.
My boyfriend gave me the green thumb last night, and now I have a green bean growing out of my anus.
Someone who cheats while playing "Guitar Hero" by placing a rubber band around the green button, limiting the number of buttons one needs to press, in order to obtain a higher score on the Hard or Expert difficulties.
"Dude! Did you hear that John got 100% on "Through The Fire and Flames???"
"Whatever. I heard he was green thumbing. I'd have to see it to believe it."