Just a note: your sphincters are actually rings of muscle which must be in control of their own stretching rather than being stretched by a third party. Therefore what you're really doing is getting them "warmed up" so you're not suddenly unable to relax when you're on the clock with your lady of choice. The more recently you warmed up those muscles, the easier it will be to open you back up again. So how recently you warm up is simply a matter of preference on your part. If you want her to bend you over and do you as soon as she walks in the room, you better have a good size plug in when she gets there! Otherwise whether you warmed up an hour ago or three hours ago, you'll have done yourself a favor and everything will be easier when she is working you open...
Also, there are kinky women everywhere! This site is just used by lots of providers in Texas. I think in Colorado all the action is split up between a bunch of different boards. I know a lady in Denver if you ever need a recommendation!
