This is a way of marking territory if they are rubbing the sides of their faces on the object. Cats have scent glands around their lips and on their chins. The facial pheromones that they mark with are signals of a happy or calm cat to other cats.
The part that simultaneously enables the axle to flex while transmitting the driving force is called a drive axle joint, and is also known as a constant velocity (or CV) joint. The CV Boot is a ribbed, rubber flexible boot that keeps water and dirt out of the joint and the special grease inside the joint.
As shown below, the Card Verification Number (CVV) is the last three digit number printed on the signature panel located on the back of your card. The CVV/CID is a security feature that allows Ryanair and your credit card issuer to identify you as the cardholder and provide you with additional security against fraud.