This was a long time ago. I funded my first startup doing consulting work writing IVR software for an "audiotex" company (I told my friends I was a phone sex repair man). While it was a colorful client, they were the best consulting customer I ever had. Paid well, and paid on time every time. Also got to travel to interesting locales such as Guyana, Nicaragua, Italy, etc. (And yes the people staffing the phones were not attractive, and more than a few were men).
I guess that counts as prostitution.