A person who is always around, hanging on every word of a conversation or event that they are not even involved in. Usually laughing when the group laughs while hovering next to or behind everyone. The act is called Sideling, the person is the Sideler. Always down to do anything to feel involved and accepted by his or her peers. Should always carry tic tacs so you can hear them coming, so they can't sneak up and sidel you or the group without being noticed.
Will: Hey Gabe let's go get a 30 pack.
before Gabe even speaks the sideler chimes in with