Vibrating Cylinder
How many guys have tried holding a vibrator against the side of the cylinder while pumping? I’m not talking about a 6 inch dildo buzzing vibrator, but a strong penetration vibrator for muscle massage.
The sensation is very powerful and for guys having trouble staying erect in the tube, this for me produces my biggest hard-ons, and therefore helps greatly in achieving a maximum post pump effect.
You can try various locations along the length of the cylinder to hold the vibrator, but for me, it is strongest when the vibrator is held out near the end of the cylinder.