It depends on how you mean it.
If you mean "Mom is crazy." it would be "Mamí está loca."
If you mean "Mom is clinically crazy." (she is in a mental institution) it would be "Mamí es loca."
saying your mom
Bésame el trasero that's how u say you are crazy about me
loco
You can say "Estoy loco(a)".
¿Eres loco?
Me vuelves loco/a.
No estoy loco
Estamos locos
You say, "tortuga loca."
You could say "Sombrero loco".
no demente, desquisiado, son others ways to say crazy.
loco por ella