There are some spoilers if you haven't played through the whole game.
Note that these endings are Lust Doll endings, I am waiting for LD+ to get more advanced before attempting a playthrough.
Most of the bad endings can be avoided if you heed the game's warnings, ie. "You have a feeling that once you enter, it will not be easy to get out"
Also remember to save frequently unlike me. That's why I died alot on my first playthrough.
I hope this helps.
Current endings as I can remember: (Please note that I have forgotten much of the real ending names as I wrote all this from memory.)
Bad Ends:
Breast slave
Sex slave
Foot slave
Oragsm Denial in machine chair
Mistrya's slave (there are a few ways to get this ending; losing to parasite boss in Science tower, and then surrendering to Mistrya, etc.) Note that the mentioned is not the only way to achieve this
Infected by meat parasite (a few ways to get this ending; usually losing to a meat infected man/woman will not cause you to get a bad end but one of the ways you get this ending is through losing to parasite boss (as mentioned above) and then choosing not to surrender to Mistrya) Note that the mentioned is not the only way to achieve this
Devoured by meat parasite core (not sure about legitimate name of this ending, you have to fall into meat parasite cavern. This is achievable when finding Linda in the military base after killing the parasite core in the science tower. This ending is also achievable on the way to the meat cavern depths to turn yourself into a parasite demon if you fall through a hole)
Captured by Master's servants
Broken Rinny's Mind 1
Broken Rinny's Mind 2 (In both 1 and 2 you will be captured by Liltith and suffer through a few days of torture in her dungeon. Rinny surrenders due to lack of orgasm after on the edge for so long)
Killed by Don
Losing to Scythera in milk store
Losing the challenge you have to attempt before raiding the tomb in Sunken Pyramid (Nagas' toy ending)
In Upper New Ark, enter gallery, enter secret room and open the notebook (Cast in paper mache ending)
Good Ends:
Rinny
Mistrya
Fawn
Linda
Miscellaneous:
Alien Milk Slave
Please tell me if I missed anything. Again, hope this helps!