Meaning
What does Blanket Party mean?
Blanket Party is a form or corporal punishment or initiation ceremony in which the attacker restrains the victim’s entire body with a heavy blanket and beats them until the person passes out or is basically half dead.
The attackers usually strike the victim with a solid object, like a rock, or a soap wrapped into a towel. In most cases “Blanket Parties” happen in the military or police.
It happens usually at night, and these attacks unfortunately are mainly targeted to suspected gay people in the military.
Origin
What's the origin of Blanket Party?
The “Blanket Party” was popularized in the 1987 movie, Full Metal Jacket, in which members on a basic training platoon perform this punishment on an inadequate member of the group.
The origin of the term comes from the beginning of the attack where they throw the heavy blanket on the person, so they can’t escape, fight back and most importantly can’t recognize their attackers.
Spread & Usage
How did Blanket Party spread?
There are various military based movies having scene of members performing “Blanket Parties” on another member of the group.
Such as The Shield series, where in the first and also in the second season you can witness officers giving a transsexual prostitute a “Blanket Party”.
On Urban Dictionary the first entry was written in 2003, and there is an entire page dedicated to this term on Wikipedia which was last edited on 10 June 2020.

External resources
- Urban Dictionary – Blanket Party