I know that feeling, it was like that for me when I had a Vulcan 900. It was actually dangerous! Coming off the interstate I had been riding for almost 2 hours I get to a stop light, I had a really hard time moving my legs to put a foot down at a stop light! I almost dropped it!
I thought that different seats might only alleviate the issue but they would never fix the ergonomics, that bike just didn't fit me. That was just one more thing I didn't like about it, so I sold it.
The stock seat actually pushes you forward, so it should keep you from putting too much pressure on the tailbone. Do you have a stock seat? A bit of forward lean will also help, does the bike have risers? If it does, take them off!