You say, "tortuga loca."
Tortue folle.
Your mother is a crazy turtle.
loco
Bésame el trasero that's how u say you are crazy about me
You can say "Estoy loco(a)".
¿Eres loco?
Estamos locos
Me vuelves loco/a.
No estoy loco
You would say las tortugas.
You could say "Sombrero loco".
no demente, desquisiado, son others ways to say crazy.