Vicky Smith many thanks for the punchline...
Jack caught the Doctor listening outside the galley to a conversation going on inside the galley.
"But tell me, Rose, you can't help but notice...it's very well packaged." Jack silently looked at the Doctor with a grin.
"I'm not telling, Martha!"
"Go on, blondie, spill!" said Donna with a chuckle.
"Can't, the Doctor would never forgive me!"
"He'd never know!" exclaimed Martha.
"If you don't tell us, Rose, we will have to try and find out for ourselves...you know...sneak a peak?"
"Don't you dare!"
"Well we know about Jack's!" This time the Doctor gave Jack a wide grin.
"Who doesn't? He's been flashing his all around the TARDIS!" said Rose, bored.
"We could ask him?" suggested Martha to Donna.
"But it wouldn't be a surprise then!" she replied sulkily.
"Well you can't have it both ways...if you want to find out then you'll just have to go to bed and unwrap them in the morning with everyone else!"