.com is an instaneous response to cap off a sentence or other statement. It should be used in everyday conversation in part with other such statements like a billion or eat babies even your mom
X: "I had pork last night."
Y: ".com!"
X: "What are you doing later?"
Y: "Eating babies.com!"
X: "How many would you like?"
Y: "A billion!"
X: "No .com?"
Y: ".COM!!!!!!!!!!!!"
I don’t fucking ask your dad oh wait your dads cheating on your mom and your on urban dictionarytrying to drown the sound of you being a goddanm mistake