I was supposed to but it hurt waaaaay too bad so I didn't. I just poked at it every now and then to make sure it was going down the way it was supposed to. I don't remember how long it took.
When I poked at it enough to make it contract I could feel the top of it until it was behind my pubic bone again. I'm pretty small in that area (well I wasn't after giving birth to twins LOL) so it wasn't a problem for me to know where it was. If you can't tell where it is I wouldn't even bother. Your doctor will be able to tell you at your check-up if there's a problem.
Re: c/s mommas
How do you know it's going down the way it's supposed to? ?I carry my weight there so I don't know if it's going down the right way :-)?