Ok mmm... Lets see what I can come up with in the time it takes to type.
One idea I thought of is having you wear a skirt or so, then have a rope tied to balls and Mistress would lead around hopefully around stairs that people can see under.
One good idea would be to order food, and have you answer the door in a fun way. Such as bound or in a dress or nightie some fun things of that nature..
You can always do something where you wear a tramp stamp sorta speak that says Want to fuck here, ask how with an arrow leading to your bum and have it shown around people even delivery
You can always write cumliker or licker on your face or forehead
In public or around some people your Mistress can call you a degrading name like Bitch, slut or pig in front of others and spank your ass
Mistress can tie a rope to penis or balls and every time she needs you to pay attention she can pull on it and have others do the same.
She can have you go to a store to try on sexy cloths and pose for her and anyone around. even if doing in a dressing room some people can peak in a open door as you show her the outfit.
You can have a vibrator in your bum and every so often Mistress can ask you how the vibrator doing specially in front of other check out lines so on, people pretend to not hear there but they do. And she can ask if you need new batteries to.
She can take you to a park or so dressed as a maid and with a bell on your cock in some way and maybe your collar to, so this way you ring and people will look at you, you can knee beside her and get her what she wants you to get even if its a stick with your mouth. Then she can have a crop and smack your balls or butt every so often for not behaving well or doing something wrong or because you was too slow getting that hot dog, even if it was lunch time and a long line...
Thats all i have >> hope you like any or some of them I know I do ^^ lol
If anything you are free to PM for any reason (need ideas or want different ideas or to talk out ideas or help improve an idea)