i don't know about the jerking off thing and taping it. but if you continuously told her how sex she is that would definitely make her feel good. she probably gained a little weight after the baby and you letting her know you stil thinks she is hott ,will make her more comfortable.
I guess she might, but it seems kind of strange to me. I don't think I would like it. You don't exactly say, but this is your baby we're talking about, right?