I want to learn to play the guitar, because I want to finger A Minor.
I don't find it funny to joke about assault.
I think you know what finger I'd like to play with.
This type of joke only trivializes the real harm caused to victims of molestation. Joking about sexually assaulting children is very offensive to most people including myself. You should be sympathizing with the victims instead of aligning yourself with the perpetrator.