I think this quesiton is easily solved with a little research. Let me tell you a little story:
This one time, at the gym, I was bored of my usual routine so I decided to do something a little more interesting. Luckily, I had a few tubs of vasoline handy and so took off my pants and underwear (but left my favorite pair of argile socks on my feet), and rubbed a healthy portion of it all over my ass cheeks. I also rubbed a goodly amount in a long straight line on the tile floor to get it nice and lubed up. I then proceeded to take a running start, drop to my ass, and slide across the floor, all the while keeping my feet and hands up in the air. Needless to say, I was wearing a helmet as that kind of activity can be quite hazardous and should not be attempted without proper cranial protection (uou that means you!). Anyway, so I slid a full 6 meters before my ass cheeks began to burn so badly that I had to get up off the floor - you gotta watch for that and 6 meters is a pretty universal distance for this particular exercise. I left about 5 minutes between each 'set'. After about a half hour of doing that, I got bored again and so began incorporating dumbells into the 'exercise' - I lined a bunch up at the end of my vasoline trail and tried to knock as many over as I could using my ass. It was fun until the gym owner finally asked me to put my pants back on and never to return to that gym again. Well, I left alright, but I most certainly did NOT put my pants back on. Instead, I took the rest of my clothes off and covered the rest of me with an ample coating of vasoline and then went to the parking lot, straddled that jackasses car and began sweating like a pig. Actually, the beads of sweat that form on a vasoline-covered body are quite mesmerizing and they make an intricate path as they slide off your body. I highly recommend that particular exercise. Enjoy. Great for getting ripped.