A quadbag is when four people simotaneously t-bag one person at the same time. The "quadbagee" has four different scrotems in his/her mouth. Quadbagging is the ultimate form of pwnage, and is extremely rare to see virtually (in Halo 2) or in real life.
Someone or something that bites your ankles.
To a postman, an ankle biter is often known as a dog.
To an adult, an ankle biter may be a toddler.
To hikers, an ankle biter is sometimes a tick.
And so on.