Oldboy wrote:I purchased an Erecaid.
But
I can't seal the pump around the penis, so I can't create a vacuum.
how can i solve?
Couple of things:
One is to keep your pubic hair trimmed well; too much hair will interfere with the seal.
Second is to 'grease' the very end of the tube ahead of time with a gel type of lube. Then press the end of tube firmly against your groin to ensure good contact.
That is what works for me; the seal is so tight that I can't pull the tube off without releasing the pressure manually.