My new girlfriend's car got a flat tire as we were on our way to see my parents, so I called them up and said, "Sorry, Mum, I'm going to be late—my girlfriend's got a puncture."
"Oh, John!" she sighed. "I thought you had a real one this time."
Explanation: OP is hoping this one blows up.
In British slang, "puncture" can mean both:
- A hole in a tire
- A hole/leak in an inflatable object (like a sex doll).