Originally Posted by marinera
Do they require sleeves?
Not in my opinion. They are made of 6 mm material, nicely rounded and I have had no irritation or pain from modest pumping between 0 and -5.
I did buy a silicone sleeve just to be on the safe side, and have tried it. The Ø is only 3 cm. Any engorgement not to mention erection makes entry difficult even when both sleeve and penis are well lubricated.
I notice that when using the sleeve the gauge will easily read as much as -8, a pressure that I am never close to without the sleeve. Can any pumping connoisseurs here explain the principles at work for this discrepancy?