How big a tarp do you need for tarp surfing?

I wanna tarp surf this week and i have a tarp that about 20x25, is that big enough to use for tarp surfing?|||Tarp surfing is an art form and should not be attempted on a generic old tarp unless your a fan of tarp burn, a nice roll of polyethylene sheeting is what you want, thicker the better, find it at home depot and places like that, 50 ft is about the minimum, any shorter you''ll get grass up your crack,