in the resource room when he offers resources for adrenaline (which I rejected as I did a virgin run).
Infinite dungeon exchange list (not exhaustive):
1. Skeleton key for chests (30 blue currency)
2. Improved grenade launcher/molotovs which also inflict burn on the player.
3. One time 50% recovery to HP, MP, VP.
You can avoid losing virginity to the Commissioner by offering anal. There was a bug in v1.0.7 where you could still be fertilized with his DNA (-2% Max HP, but heal 2% HP each time he appears), but was fixed in v1.0.8.
The Lockpick is an accessory you can equip to open Chests without spending 100 HP or 1 Shotgun ammo, but there's still a chance of an empty chest or an ambush. Uneqip before boss fights, of course.
The Virus Vest gives 5% damage resist, but gives 2 Virus Points per step. Best used before Boss fights.
The Virus Dagger keeps the first Dagger per encounter from breaking when used to escape restraint, but gives 1 Virus Point per step.
The Lighter lets Molotovs inflict 20% damage when thrown, but also burns you.
The Flashlight prevents you from getting lost exploring, but gives 2 Virus Points per step. If you really want to avoid a 5-floor change (e.g., the Hallway that boosts adrenaline per step), equip the Flashlight during floors ending in 2 or 7 (floor change triggers on floors ending in 1 or 6).
It's easier to farm skills if you unlock the Caress sex skill (50% chance at stealing an item, including skills), but the only enemy that can penetrate just anally is the Jorogumo.