Gay slang for having sex while sitting on a penis. A man who likes to "sit in the grass" is one who likes to be penetrated while sitting on his partner's penis. The "grass" in the idiom is pubic hair.

the occupying of an area by a large group of protesters, effectively blocking an area off to a particular person or people until removal by force or the achievement of the goal (popularized in The U.S. by the Civil Rights Movement)

it means to sit in the garage (fridge) when the weather is cold and smoke a bowl (fire)

A phrase often heard in response to an outlandishly stupid statement. This plainly means, that someone has said somthing so stupid, or you are in such disagreement, that the person who has made the statement, must now leave the group discussion to suclude himself from the discussion.

to literally fill a tub with chocolate and sit in it. The chocolate actually works as a great shaving gel. Note:it is unsanitary to eat the chocolate

To take up an unoccupied chair or space to either sit in, sleep in, or whatever in.

(a)When you know you're going into a area or situation were your person will receive a whole lot of verbal abuse.
(b)When you're going to party your brains out in some locale outside your city.