Tuchises is a slang term that refers to the buttocks or behind. There are several synonyms that can be used for this word, including derriere, booty, bum, posterior, gluteus maximus, backside, rear-end, and back bumper. These terms are often used humorously or in informal settings. It is important to note that some of these words may be considered offensive or vulgar in certain contexts, so it's essential to choose the right word based on the situation. Overall, whether you're looking for a more polite term to use in a professional setting or a playful synonym to use with friends, there are many great options to choose from.