well, perhaps

I don't know what you do at your work but sometimes at mine I like to pet people's arms and do a bad impression of a purring cat (it sounds more like a bad impression of a dove or a wookie)

Right then.

A couple of days ago -

Me: :petting arm and purring:
M: You need help.
Me: :shrugs and continues petting and purring:

The next day -

Me: :pets arm and doesn't purr:
M: You should purr when you do that.