One of ways.
Specific order may vay, but:
1)Start with 10 sluttyness (take all sluttyness-rising options at start). I recommend using «nerd» Beth, her starting glasses and shoes will give +3 attractiveness total, which will speed out seduction of some characters.
2)Do two scenes with gnome, they will rise sluttyness AND temporarily rise your lust to maximum, which itself give you some temporal sluttyness (+1 for each 10 lust points). Defeat by rats, but only up to 5 times.
3)Quickly, before lust will drop too low, give Elf trader blow-job. Repeat 3 more times, until it stop rise your sluttyness any more.
4)Lost to Slime Boss 4 times, it quickly rise your sluttyness high enough fo Beth to «upgrade» blow-job scene.
5)Give elf trader another 4 BJ, it will give you more sluttyness (one last time). Since now he will cum in mouth (not on face), it will give you additional sluttyness. If you skip low-level scenes, you will receive less sluttyness in total, hence this specific order.
6)Lure Red Wolf to elf trader or guardian, give them HJ/BJ for rising lust, and then lost to Red Wolf when lust is higher than 50%, if Beth cum from this scene, you will receive more sluttyness. Better drop all armor if you want to keep it, or it will be destroyed.
7)Lose to Ent. It can be found in north-western corner of forest.
8)Defeat Slime Boss and have scene with elf-girl for additional sluttyness.
9)With high lust, you can have 80+ sluttyness long enough to give pig trader HJ, which will rise it once more. When sluttyness is on 80+, you can drop bra if you want. If your lust drop too low, rise it with Elf or guardian. Be sure to use green portal rune to teleport to pig trader. Otherwise, you can buy or find some books, they will give you more lust on «consume».