Derived from the term "Sailor", as in: excuse me sir, there appears to be something on your heel. (The person then looks at their heel) to which the phrase "oooohhh hello Sailor" is then used.
I was meant to be meeting Lewie at 7 in the bar and he didn't turn up until 9.30. Heels.
John was heeling in his cubicle waiting for the opportune time to run to the restroom for some much needed relief.