Dripping oil from whatyoumaycalleit cover? Help!

[KikeXJ]

Hey Guys need your help, my bike is leaking very small amount of oil form the round cover on the bottom, don't really know how's it called and what is it and what can I do? The manual I downloaded it only covers basic maintenance. Will download a more complete manual tonight at home since I'm at work and cant download stuff here. But wanted your opinion first before I screw up the motor.
Bike motor illiterate!! :wallbash: