Public Indecency on bus

Around 12:40 I got the 412 from Toowong to Chancellors place. The bus was very full and I was sitting in the last row, but next to me was this man that was very clearly masturbating. He was attempting to cover himself with one of those cooler grocery bags but still continued to do it. As the bus was full I’m not sure if many others noticed it but I did inform the bus driver. I was wondering if anyone knew what happened or what I could do in this situation or what I should do if this happens again.