Because thyme heals all wounds. :D
Because a vasectomy would heal in seconds and he doesn't look like he'd wear a rubber or pull out.
Made you look!
He's a Thyme Lord
They've got a lot of thyme on their hands
A: A first-aid kit!
Because she wanted to be a first-aid kit !
Every time he touched a "wound" it closed.
His wounds always heel.