Just to add to @Calie’s info, but we’ve used a ‘pussy tightening gel’ and that did make Mrs Chimp feel tighter. I’m not sure if the one they currently stock is the same one, but here’s a link:
For us, Mrs Chimp mainly used kegel exercises to get her pelvic strength back after having the kids, with a smattering of kegel ball exercises thrown in for good measure. The gel was fun though, but I don’t know if it would have worked/felt the same without the pelvic exercises as well.
There was also this topic, which may have some useful info in?