Teletext services were eclipsed in the mid-'90s by the advent of the World Wide Web, but those of us who are old enough to remember them will feel a frisson of naughty nostalgia upon revisiting these ads for adult services.
Part of what's so cool about them is so much is left to the imagination. Like the way we sext with emoji now.
Our pals at Dangerous Minds did a fun related post here. The massive cache of thumbs is from lordnkon.tumblr.com via text-mode.tumblr.com.