The act of feeding your stepsister mass amount of Taco Bell and then proceeding to shove your fist up her ass as you would a puppet, then grab a fistful of fiery, watery, Taco Bell shit and whisper in her ear in a Kermit voice saying, “gee the swamp sure is nice”
Typically used in banter, a soggy pigeon is a person who doesn't deserve your time, but you won't say it to their face because your afraid of socialising.