Originally Posted by
AzTallRider
How is the angle of your saddle? Is it possible that it is angled a bit down, and that is causing you to slide forward? As a general rule, your butt is going to find the natural place that it fits on the saddle, but that is partly dependent on angle.
^Yep, this! You should be able to tip the front of the saddle up just a bit and locate your sits bones right on the wide portion of the saddle. If you start to get numbness in your genitals or keep sliding too far back you have gone too far.
Having too low a saddle is also hard on the knees and can cause pain in the kneecaps.