Not that I mind mature content as I am a "mature" adult. But is there anyway to turn off the mature content "cut scenes".

Right-click when the cutscene starts. Look for a "right click to skip" prompt at top left. Right-click again.

This is also handy for skipping a cutscene you've seen too many times, such as the umpteenth time you've been clobbered by the Kayran and don't want to sit through Sile summoning it yet again.

I've had a look at the mods over at The Witcher Nexus and there doesn't appear to be anything. Best I can suggest is either to skip (Y with a gamepad, not sure what with a keyboard) the cutscene or else remove the Succubus/Elf files from your CookedPC folder, essentially creating a censored version. Don't delete them just in case something breaks and you need to put them back.

For the other parts - Triss, Ves etc - just avoid the dialogue choices that will lead to sex.

Man, we Americans hate nudity.

http://www.youtube.com/watch?v=EA1reeONJrE

The first thing that comes to mind is why would you want to?
You don't have to have sex in this game, also, don't buy mature games for your kids people, although your kids have probably already seen more mature stuff then can be found even in the most obscene mainstream video games .

Why would you want to do that? (and this is a serious question).

Witcher was built on the concept of maturity and elements you see and experience in the game are as close to what you would experience in real life if you were living in a similar age and setting.

So by switching them off you are robbing yourself of some outstanding experiences that are meant to provoke a reaction or two from you (the player)