1) Any device/pill that increases the size of the penis.
2) An object such as a dildo, remote control, plastic bottle, or anything else possibly used in place of the actual penis, to simulate sex(usually by a male that "will not touch that stanky ass pussy", or a lonely female).
3) A glorious gift that few possess that enables a male to get an instant erection on demand, regardless of the time or place.
1) Phil: "Hey man can I borrow some extendo-dick pills like Cialis, Viagra, Levitra, Extenze or somethin like that?"
Jeff: "Sure. Why, you got a date?"
Phil: "Nope, just wanna try it out."
2)Jeff: "I couldn't bring myself to fuck her without a condom, so I just bent her over and used the DirecTv remote, and went through the motions... And by some miracle I tivoed I Am Legend with Will Smith."
Phil: "What, Jeff? I wasn't paying attention. Your remote's buttons are stuck."*smacks on couch* "Maybe i can bite it..."
3) All that cock push-up training really came through when i got laid in an elevator by pushing the button of the girl's floor who came in after me... with my dick. Thank you extendo-dick.