I did once with my ex-gf in a female toilet in a mall in Australia. Many years ago.
After staying with her for 1 yr but all the time did it under protected sex. One day, strolling in the mall and was feeling damn horny after seeing those young Aussie chicks romping the mall. Suggest to my gf and she unexpectly agreed. Head straight to the toilet and have a quickie. Feeling was fantastic since it was first time w/o cap.