What excuse would you fabricate to explain an inexplicable attack?

Your best friend is taking a nap on the floor. Suddenly, you are faced with a bizzare existential problem: He/she is going to die unless you kick this slumbering friend, as hard as you can, in the rib cage. If you don’t do this, e/she will never wake up. However, you can never explain your actions. If you later inform your friend that you did this to save their life, your friend will die from that.
So you have to kick a sleeping friend in the ribs, and you can’t explain why.
Since you cannot tell your friend the truth, what excuse will you fabricate to explain this seemingly inexplicable attack?