Kevin's head

"It's a bit worrying that you're this tired after warming up," said Kevin, my gym instructor and, officially, the most annoying person I have ever met.
I wheezed something about being okay.
"Let's move on to the cross trainer," he said, as he lifted me, all limp, from the exercise bike to the next machine.

I surveyed the device and thought of ways to appear like I was working out without actually exerting myself any further. I decided this was best achieved by simply pulling on the bars with my arms, back and forth, propelling myself into some sort of exercise. As I did, Kevin watched my heart rate on the monitor and calculated, in his tiny head, at which point I should stop.
"You're 23..." he muttered, "220 minus..." Then, looking again at the monitor, "Yep. Stop there." With that he slammed the stop button and I became all limp again.

The next thing I know, I'm half way home, limp on a bench, about to throw up. But all I see is a bin with a roof on and an opening around its sides large enough to deposit a banana skin or an apple core. With little choice and just enough turgidity in my neck to tilt it I threw up the best I could into its little opening. The turgidity in my neck gave way and I slumped back into the bench, all limp. I imagined that the bin, oozing with my vomit, was Kevin's head, and suddenly felt much, much better.