Parapraxis, Perhaps

I'm usually overexcited about whatever I'm teaching, and I'll speak quickly, often combining words, etc.

Once, when trying to say "start," I said "shart," much to my students' delight. I laughed along with them, thinking it amusing, too. A few minutes later, I said, "Oh! It's funny because it sounds like 'fart.'"

"It's a word, Ms. C!" they assured me. "Haven't you seen [insert movie title I don't remember]?" Of course I hadn't; I told them I didn't watch that rubbish. But when everyone refused to tell me what it meant, I consulted the online urban dictionary.

"Oh!" I said. "It's a poop fart!" More hysterical laughter.