Gate travel via wormhole is one way. A person cannot go through the gate, leave it open, and then step back through it. The gate has to be stopped and then restarted from the opposite planet in order to travel back to the other end. The only thing thing that can travel two ways through the gate are radio waves (which the MALP transmits back to Earth).
The wormhole automatically shuts down after 38 minutes
A theoretical sexual maneuver based on the scientific application of the wormhole. One’s fist is inserted into either the anus or vagina of another and is pushed deeper and deeper until the hand comes out of the mouth. The fisting of the urethra is also acceptable. A lot easier on dead people.