Every time Don puts his hand there and that is pretty often.
We do have a surprise every now and then. A mouse might just shoot up your leg for no apparent reason. They come around because of the birdseed but very rarely. Once Don was working and "zippy" as we affectionately named her, showed up. He noticed her and she panicked. I was in the kitchen and all of the sudden Don lept straight up out of his chair!. Little zippy shot out from the bottom of his left-leg sweat pants, It freaked all three of us out. We haven't seen zippy since he hurled her through the kitchen.
It's those odd things that go bump... and up your leg in the night. :P!