This occurs when after impregnated a girl and after the baby is "spat" out a girls stomach becomes stretched and worn out, this aslo applies to the breasts. The parts begin to sag and look wrinkled and old.
I'm gonna dump my girlfriend because after last year she became a 18 year old grandma, or looks like one.
when a woman is on the bed and the guy is on the ground, giving oral
man me and my girl were doing the grandma all night