Mamono Kurai no Boukensha - Ch. 2.2

[MangaDex]

 

[CivD666]

Iron sack? I understand all the other skills, but he got a skill to protect the family jewels from eating monster meat?

 

[Miserys_End]

Iron sack? I understand all the other skills, but he got a skill to protect the family jewels from eating monster meat?

Likely just a mistranslation of something similar to cast iron stomach.