I'm Petting My Dog

Specifically when a male masturbates or strokes his erect genitalia and would like someone to know it. Used mainly for describing to a significant other over phone calls or public that you are/have masturbating. The reason you would use this term and not just outright say it would be due to things like: They're parents are in the room, you're in a public place, they have you on phone speaker, etc.

"Hey,"
"Hey!"
"Am I on speaker?"
"Yeah, why?"
"Oh I'm just calling to let you know I'm petting my dog.."
"Oh..."
*Takes off speaker*