hi fellas,
as someone who used both sex toy pump and soma therapy pump, I can easily attest that there is a big difference in terms of effectivity.
the medical quality ( soma therapy ) is way better in inducing erection and seal it properly. the most important thing is that u have to use a lot of soma therapy lube on ur penis and on the pump itself.
I also noticed that the presence of groin hair prevents the ved from working as it disrupts the sealing process and hence the erection induction. so basically lots of lube and being hairless down there.
other than that, just follow Oldman regime