Origins: First to properly execute an up periscope one must first " blow ballast " by farting in the hot tub.
If undetected by the other occupants, preferably female, the "scope master" will raise his body until the head of his penis slowly breaks the surface. If he remains undetected he will slowly continue to push his penis farther out of the water until detected.
When detected he will yell "Down Scope" and rapidly pull his body downwards while acting as if nothing happened. If he remains undetected that means the female occupants of the hot tub are receptive or totally hammered, in either case, this often results in a "torpedo" attack after he yells UP SCOPE!
2.A mythical command often seen in WWII movies to raise the periscope. Up periscope is not used by modern submariners. The officer of the deck will inform the watch standers submarines control room the he is "Raising Number 1 ( or # 2 ) scope." at which time he will rotate the periscope ring that activates the raising / lowering mechanism.
2. "Up Periscope!" Ensign Jones commanded. The watch standers looked at each other in quizzical disbelief. Don't you mean "Raising Number 1 scope?" asked the Cheif of the Watch. " "Uh...right Cheif"...Ensign Jones demurred.
2) bath or shower game for typically one very lonly man
(n.) Bath-time fun for young boys.