I heard from a friend to rub some vasoline between the crack but that seems weird to me.
The standing up thing is good in theory, but in practice it doesn't always work that way. Whoops yes, its a no brainer. When it gets really technical, and its "get through any way you can", textbook style goes out the window, especially for us Senior B riders. If your not tall you have to sit to get a foot down when needed in some of the rock gardens and other fun places.
How about this for a new product: Butt grease in a giant tube like a chapstick, about the size of a grease gun cartridge. No messy hands! We can call it the "Crack Stick"
Thats the stuff ! I can only imagine the results from that Google.