Verb | The act of 'slipping' something, such as an idea, political argument, or theory/concept into a conversation where it does not really fit; like using a shoehorn / shoe-horn to slip a foot into a tight-fitting shoe

It's the sweat that accumilates under big boobs

The act of inserting someone else's foot into your body cavity, normally the anus or vagina, for the purpose of stimulation and, eventually, climax.

The act of forcibly inserting ones knob, shaft and entire scrotum into an unsuspecting and unwilling females vaginal canal.

After a night of heavy, HEAVY drinking, a girl wants to have sexual congress with you. However, your pink crayon isn't up to the task. You're determined, however, and decide to cram Ol' Floppy inside of her. You're determined to get it up, but it ain't happening. You keep flaccidly stabbing away with zero results. She goes home deeply disappointed.