It was called "mail order."
The shortcoming of mail order was finding an advertisement for what you were looking for. That usually entailed buying some kind of naughty magazine in the first place and that was often a big step to undertake for some people, if you could even find any in your vicinity. If you lived outside a big city with a 'seedier'area, I'm sure it might have been difficult in the past, even more so if you lived in a very traditionally minded area or where everyone knew everyone else (the horror of such communities!).
Moreover, I'm pretty certain that you had to look beyond mags like Playboy to find any real sexual devices advertised.
That's how I got my first Sherema bag
Where did you find an ad for a Sherema bag? Maybe in a mag like 'Water & Power'? You gotta admit, not the kind of publication on sale at the local newsstand ... ha ha. More likely you'd find it at a sex shop and that again entailed an element of daring for some people.