It's not missionary and anal, it's missionary and anal beads, lol. Do missionary until you've maxed the two main stats it buffs (Sex Appeal and Technique), then start doing anal beads (Perverse) until you've got around 5-10 in all stats. If the girl is F or F+, it's about 10-15 max stats. You should be able to start making money reliably at the starting area at that point.
A little trick to that is that for some reason if you keep doing missionary for a while, eventually her Perversion will go up to 1 instead of 0, so you can save losing some Sex Appeal/Technique once you switch to anal beads. If you don't do that, an F or F+ girl might drop below the stat requirements for the 1st or 2nd sex location, so it's actually pretty helpful. This should get your girl to 25-30ish obedience as well.
You can unlock more positions in the shop, should be easy to find with the translation.