How pill can make your cock bigger? Put your cock in the pump and see how much you can pump. This is external pressure. If you taking good quality pills you could see similar results thanks to pills pushing more blood from inside to your penis. Simples. If your penis is flexible you could see some of the gains even stay. Especially girth seems to improve from 3-4 month courses.
BUT
If you want to see permanent gains in girth and length then you should take pills AND perform penis exercises.
Simples.
Pills improve bloodflow which in turn ensures you get most out of exercises (like taking supplements when going to the gym). It is important especially if your erection strength started to decline (25+ of age, unhealthy lifestyle, huge stress, etc causes) / or your sex frequency is almost as often as x-mass.
Gains... depends on many factors, like you age, flexibility of your penis, thickness of your penis etc; You could expect 1 - 1.5 inches in around 3-4 month period if you are normal and can follow the instructions and stick to the routines.
So if you're taking some $20/mo pills and waiting on magic to happen... well... ... ....
Hope this gives you an idea of how the things work around here
Ah.. sorry for mistakes... tired!