I want to play a practical joke on a colleague of mine and I need an accomplice. My accomplice needs to be a hot looking actress and model, slim, white, less than 30, and able to flirt really well.

This colleague of mine is always boasting about how good he is with the ladies and how big his dick is, etc.

So, here's the deal. A hot looking girl (that's you) dressed in a really professional manner (ie. like you just finished a business meeting), should meet him in a bar and flirt with him.

You should slowly heat things up for a while, flirting with him, then start making out with him, and generally get him really hot.

Then, you go with him to his hotel room. Make out a bit more, and start undressing like you might have sex, and get him to undress. But as soon as he pulls out his penis, you should burst out laughing about how small it is, and how much bigger "normal-sized" dicks are, crack some small-penis jokes, etc. You can back this up by saying that you've seen 50-100 guys' penises, so you'd really know.

What happens after that is up to you as long as you stay true to character.

So, any takers?

That sounds like it could go poorly.  What if he really does not have a large member and only boasts to hide his embarrassment?!  You could damage the poor man!

Why not just convince him to show you his penis.  Or if he won't, try and get a good look at it in a shower locker room or something.

Then when you see his dick, just start laughing and tell him how you know a lot of other guys with much bigger dicks.  Tell him his dick looks gross and small.

Trust me this will be even funnier than your idea.