Could you share a urethral item? It's what I'm looking for but I got no idea how to do custom items etc.
Kinda, but it requires that you edit one of your save game xml files in the 'game folder/data/saves' folder. As the save file says:
<!--If you want to edit any of these values, just be warned that it might break the game...-->
Instead of doing that, it'd be relatively simple to just enchant a potion to instantly alter the penile or vaginal urethra to be looser (any capacity greater than zero is penetrable, depth is how long of a cock or tail will fit, and plasticity and elasticity are how much the orifice permanently deforms and stretches). Use a potion that would alter the drinker's form to change shape as a base, like 'vanilla water' for human parts (that name might be incorrect). The base creature type doesn't matter unless you're adding parts (arms, penises, vaginas, etc)
Enchanting a piece of clothing or a piercing will change the wearer over time as well. The urethra options are found under the penile and vaginal enchantments sections. There's an enchantment tutorial when playing a new game, after you absorb your first essences. Sealing enchantment can be used to make the item hard or impossible to remove.
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If you don't want to enchant a potion or item, here's something from a save of mine that will alter the vaginal urethra to have just a little capacity (looseness), a lot of depth, be very resilient to stretching, to keep its original shape, and to be puffy and muscled. Multiple uses of this stack of 'Teddy bear potions' will simply increase depth, retain 'tight' looseness, and have a very rubbery and resilient urethra. I don't have any saves that alter the penile urethra.
This goes in the '<itemsInInventory>' section of your character's section in the save file. Good luck.
Code:
<item colour="BASE_TAN" count="11" id="GIFT_TEDDY_BEAR" name="Zexy Angelic Urethra">
<itemEffects>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_CAPACITY_2" potency="MAJOR_DRAIN" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_CAPACITY_2" potency="MINOR_BOOST" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_DEPTH_2" potency="MAJOR_BOOST" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_ELASTICITY_2" potency="MAJOR_BOOST" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_PLASTICITY_2" potency="MAJOR_DRAIN" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_ORIFICE_PUFFY_2" potency="MINOR_BOOST" timer="1478" type="RACE_ANGEL"/>
<effect limit="0" mod1="TF_VAGINA" mod2="TF_MOD_ORIFICE_MUSCLED_2" potency="MINOR_BOOST" timer="1478" type="RACE_ANGEL"/>
</itemEffects>
</item>
