First, make sure you have a very sharp blade. Preferably a serrated one that can cut through bone. Next, apply alcohol to gauze pad and wipe over area between thigh and knee. The higher the better, though you don’t want to get too close to your equipment. Then, tie a very tight piece of tee shirt (use your own, you’ll look tougher) around the highest point that you want to cut into. After that, down a bottle of the stiffest liquor you can find, Everclear should work fine, and begin the process of regretting the decision of playing in that pickup game with other guys too old to be playing hoops. Begin to saw in strong, downward driving motions, until you are cleanly through the leg. Apply the heated muffler of a supped up bike to cauterize the wound. Get back in the game.
You have solved your hamstring problem. I can help you out with any bicep injury as well.