Should I piss in my compost bin or is my mate winding me up?

I’ve been getting some advice about getting my compost bin started from a friend.

Got my compost bin going today with their help with a mix of food waste, grass cutting and cardboard etc. then once we were done they said don’t forget to wee in it weekly. I thought they were joking but they say a weekly pee in the bin when the neighbours aren’t looking is amazing and something gardeners have been doing for thousands of years.

Am I being had here or is this legit??