If there is a whole bunch of people in a vehicle, usually more than there is supposed to be, it's "Stacked Deep".
Anytime there is an excessive amount of people crammed into a small area, it can be described as "Stacked Deep"
"Them fools was "Stacked Deep" in that chevy."
"Yo, Nigga, that party was "Stacked Deep!"
"We was "Stacked Deep" in that mufuku!"
When you are so involved with a situation and it is also one that may require assistance; when someone is a little less than waist deep in something; when you are in a situation wher your position is either extremely favorable or extremely unwanted.
"Dude I am sack deep in a sausage fest, get me outta here!"
"Dude, I was sack deep in the mud when i stepped out of my truck."
"Dude, I was sack deep in her all night!"
"Dude, I woke up and realized what i had gotten sack deep in last night!"
where you put both of the legs of your dime piece hoe on each of your shoulders and stick your johnson in her vajayjay so it feels like your johnson is in her stomach.