Office slang. To sweat the details, with much effort and sometimes pain.
Kudos to Kevin for a stellar job on the difficult project. Kevin was waxing the concrete early in the morning and late at night for weeks.
When you are talking to a person about a subject you enjoy.
Or talking to a person about a subject they or you both enjoy.
I was waxing sharp.
They were waxing sharp.
We were waxing sharp
You know you love to wax sharp about sports cars.
He was waxing sharp to me about fishing for an hour.