Let her go and bid her goodbye with a smack on the ass

Okay, that's been enough fun for now, you think to yourself. You decide to release her and let her slink back home rather than putting her through any more ordeals. One second she's tied up, then a blur of motion sends her spinning as you remove her restraints.

When she comes to a halt, she realizes her hands and legs are free, and she's no longer gagged. She doesn't waste any time to use them to try and cover herself, because as magnanimous as you are you'll probably be taking the clothes with you. Having been spun around, she's standing with her ass turned towards you.

"..Oh dear goddess please help me"

You step up behind her, put a hand on one shoulder gently guiding her to start walking away, leaving her both relieved and a little perplexed, and then follow up with a firm smack on her behind to really send her going. She goes "eep", ass wobbling and slowly turning red, and then she tries to run away from you, off the square, utterly disgraced and humiliated.