Sissy has to serve her mistress as a toilet

Sissy moans and begs that her mistress should finally free her from the chastity after weeks, the mistress even agrees, but only on the condition that poor Sissy serves her as a toilet and then licks everything clean. You can imagine that the unfortunate sissy is not really ‘happy’ about this option but what can she do as the mistress' property. Whereby the mistress never intended to really unlock her but the sissy didn't know that when she was being used so marvellously