Yay I'm not the only one who is a lefty! I agree, but its perfectly fine when sally from across the street does, you know the hot brunete with the eye patch and skull tattoo on her peni- VAGINA... totally what I meant to say... vagina.
My right arm of course, because how else would I masturbate? You realize that jerking off with your left arm is satanist.
Actually, using your left arm to write was considered such a few decades ago. Therefore, so would masturbating, and public nudity if you do it in front of people. So, if you wanted to, masturbate infront of old people with your left hand if you want to be the outright most horrid person on the planet.