There were basically two methods:
1. Luck. (Sometimes this method worked better than others)
2. Various personals in the local alternative newspaper or phone meetup lines.
Believe it or not method #1, while certainly a trial and error, time consuming, discouraging method, actually worked better than #2 even though there were (very) occasional tickle ads from women found this way. The people placing these ads were often flaky or came with other problems. One I met was probably alcoholic; another had weird rage issues. The most memorable was the one who actually called a government line while I was there to see if her recent ex had been released from jail. Okay...
And if you wanted to rent videos or buy magazines you had to trek down to the creepy adult store and wade through the hardcore stuff in the fetish section and hope you got lucky because, as you’ve probably heard, the pickins were unbelievably slim in those days. Sometimes even stores with fetish sections didn’t bother to carry the prehistoric tickle material, which was usually not good anyway.