can anyone help me?

Hi people please help.I was wondering if anyone knows of a excelent butt plug which isnt too big but which stays in when im walking.I bought a nice average begginner size but it refuses to stay in when i stand up to walk around.I think that the ridge isnt long enough when its inserted, simply because it just falls out.Please please please let me know of any out there that will stay in because i simply want to feel the pleasure of walking around whilst having a plugg inserted.Thanks you lot i look forward to the replys xxxx.