Liking the content so far. Reminds me of Didnapper but more lewd and can still act even when bound. Hoping to see more bondage equipment!
Some suggestions:
If possible you can add vibrator and dildos. Nipple and clit for vibrators, pussy and anal for dildos. When wearing them the strength of their vibration and thrusting can be adjusted, increasing Lust more and more. Eventually when the party member is about to reach climax they can try to hold the orgasm. But each hold will become less successful until you eventually climax. After climax you skip a turn. Also the higher the lust level the more they need to rest after climax but they can also restore HP and action points with higher levels. With equipment that provide bonuses, the strengthened vibrators can increase HP and AP recovery each turn; with dildos, orgasms can unleash an attack burst with higher strength depending on the Lust level.
If vibrators and dildos are available then maybe a trap room where sex toys littered the floor. Some need to be used to open a chest. Others are left there to entice lusty adventurers. If the party has high Lust level they'll give in and start playing with the toys. This'll attract enemies to your position with the toys still stuck inside.
Capture system where once a party member HP reaches zero there's a chance they'll be kidnapped by the enemy. You have to find them to have them rejoin. However if you decide to leave the dungeon, the party member will be left to the enemy's mercy. You can come back for them, but the more time they spend with the enemy the more corrupted they become. Eventually they may even become a lustful enemy wanting to capture you. Even when they rejoin they are still corrupted. They may bind themselves on purpose, let themselves get hit for pleasure, masturbate, or even bind their teammates instead. You may need to buy a memory erasing potion or get a mirror that pulls out all their lust and defeat that avatar to restore them to normal.
If capture system is available before a dungeon run you can choose to sell your teammates or everyone to earn some more gold. You'll be bound when entering and will need to escape before becoming permanent residents.
A hogtie gear where you cannot move. You can earn a lot of AP by resting but cannot perform any actions, not even attack. A strengthened hogtie is available where it comes with dwarven made arms and legs to allow movement and use of attacks requiring hands and feet while still tied up. Another would be a wooden horse where if hit by the enemy the hit would rock the horse, adding Lust and also causing orgasm. A strengthened wooden horse can act as a mount and allow use of skills requiring mouth.
The more you are bound the more chances of learning skills, such as having more strength when bound, the use of lust instead of AP to power skills, heightened sense with blindfolds, or regaining HP and AP but adding lust when hit.