You need to rub each other's frenulum. It doesn't work like a pounding fucking. But rather like a boys first wet dream. Were the mutual lubrication and suction interlocking allows you to self orgasm into one another.
It works like a suction cup. Spared foreskin gravitates towards locking and covering the head. As both penis erections sense a tightness, both urethras generate precum like a lubricant inside one another. The nerve endings to each penis are highly sensitive and aroused. It's comparable to an oversensitive frenulum, where each are being rubbed. Each penis head glands are hyper sensitive to cause orgasm