An occurance that happens when you are giving somebody anal and you pull out too fast, causing the suction to unload their shit and your jizz all over you.

(Significance: Toilets in a submarine have to be properly flushed, or else it will overflow or spray the contents everywhere)
Bob: "Dude, how'd it go last night?"
John: "It was good until the end..."
Bob: "Awwwww that's the most important part man!! What happened?"
John: "Well, after I finished, I got a submarine toilet"
Bob: "..... You're fucking retarded. I got you laid and this happens??"
by Black and White Saint January 26, 2011
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Those turds that aren't floaters or sinkers, they bob in-between.
Steve: Dude, check out what just invaded the crapper.

Bob: DAMN!!! That is one huge toilet submarine!
by ed! June 11, 2014
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