How To Do a Slip and Block To The Body. Becoming a More Skilled Boxer. Tom Yankello of the World Class Boxing Channel presents a boxing and pad work drill that focuses on how to do a slip and block to the body. Tom wants to remind you that the boxer and fighter should do this drill on the heavy bag and in shadowboxing. Starting this drill on the mitts or pads is great as it allows the trainer to help direct the boxer’s movement. Once this is mastered, the boxer should move onto performing the drill on the heavy bag or shadowboxing as this allows for the development of rhythm and imagination.