'Tis a skill that requires diligence, patience and effort. You must make the effort to not make an effort at all. You must be patient to do nothing. You must be diligent that you do not overexert yourself. That is how to be lazy. You must emulate the sloth.
I can be sure that tripping over is a skill. It requires a lack of balance and a degree of clumsiness. I also trip over, for no reason at all and nothing makes me fall down. I must be knock-kneed. Not so.