Right handed, I do almost everything that way...
When I first started to masturbate, I did that with my right hand too, then I remember hearing about how "if you use your other hand it's like a completely different person!", so I tried it and liked it. Long story short: now I only do it with my left hand, and as I've grown, I mainly just let my right stroke the bottom half while the left focuses on the top half/head.