Also can someone please explain they chewing gum whilst having sex part. Did they both just happen to be chewing gum when they decided to *beep* or is it supposed to add that extra something?
I would guess they did it to add some humor to the scene. If you are "just friends" you might behave in an "unromatic" way while "playing tennis," right? I thought it was clever and pretty funny, but then again I liked most of the film as a light, somewhat silly comedy and not the most important film of the century. Sometimes people take comedies to seriously and want them to be something they aren't or can't be. Remember, it all starts with the script and then what some (usually) idiot at the studio says can be made because it might make a billion or fill a screen for some "demographic."
If you are actually interested in film as an art form, check out some older ones from the early days and from good directors. Otherwise, buy some popcorn and have a great show!
Wow what the hell rattled your cage, are you always this serious when discussing something on a message board? Whats wrong, haven't been laid in a while? If you can't discuss something like a normal human being then kindly *beep* off please. Cheers!