1. N.: A phrase describing the unfortunate situation that arises when a large male member is liberally covered in lube, placed in the anus of a willing participant, thrusted in and out of said anus for upwards of five minutes (no less), then removed upon seminal emission, causing a swollen, inner tube like rectal prolapse to emerge, covered in a greasy substance composed of lube, sweat, and seminal fluid. It is considered appropriate to refer to this act as, "Givin' her (or him) the ol' greasy inner tube."
2. V.: The act of causing a greasy inner tube.
1. Sally: "Care to give me the ol' greasy inner tube tonight?"
Chuck: "What? No! Why the hell would I ever do that?"
Sally: "Well, it's either that or I bungie jump the cornfield."
Chuck: "...sigh, fine, I'll get the lube."
2. Chuck: "So, I greasy inner tubed Sally last night."
Mark: "Wow, really? I've always wanted to try that. How was it?"
Chuck: "Better than the time she made me snorkel the hot air balloon, that's for sure."