That position would be hard to explain, BRMSTN, but fun to remember. My senior year in high school, I got my Indian motorcycle and never hesitated to take interested classmates for a ride. The first one I took was a female with the strongest hand grip of all.
Although my saddle had hand grips on each side, the inexperienced rider found it more convenient to wrap her arms around my waist. The first time I 'gunned' my bike, Norma Dean's reaction was to clamp down on my dick with her right hand. This clamping and releasing continued every time I twisted the throttle and then backed off. Her dick playing, along with her tits pressing against my back, was enough to make me eager to test other riders' reactions, always telling them to wrap theirs arms around my waist to be nice and safe! Before bike days, it was generally my hand on my dick, but it was fun learning how different hands felt wrapped around it.