Even female cats can release anal glands when excited or nervous. It is normal unless like Jaqi said they are impacted or infected. Then usually you will see them scooting their butts along on the floor as if they have worms. Or they will get swollen and nasty looking. Then a trip to the vet is in order. But most like he just got overstimulated from the grooming and they released.

By the way...welcome to Pet Talk. Would love more stories about your kitty.

Denyce