These are some yo momma comebacks. Use them. They work!
"Well at least my mom doesn't get a boner every time she sees an old lady!"
"At least my mom can keep balls out of her mouth!"
"At least my mom doesn't pick her balls every night!"
"Well my mom has a pussi!"
"Well at least my dad hasn't got a pussi!"
"My mom doesn't even have chest hair!"