Can you penetrate yourself? Would be more interesting if there were other varying aspects, like thicker tips that take longer to go in, thicker shafts that are less flexible, bigger balls that provide more protection or wider anus(?) that's easier to penetrate. Maybe some additional skills like shooting various fluids that do various things like slowing down the enemy dick, or dropping pubes that entangle it. With just the length that changes, it seems like the game would get boring quickly.