it's about the pointer or the cursor or something like that !? LOL please help me !?

[ShawtySaidoun]

So i saw this video on youtube [http://www.youtube.com/watch?v=HETmg3w92Nk&feature=related] i notice that every time she/he clicks on something there is this red thing... i was just wonder how she/he did this ? can you please tell me how she/he did this ? i already wen to muse setting and all but i just can't find it :S --'