The crux of the issue here is that a waifu is imagination personified. By definition, she is how you fantasize her, and this thought is aided in taking form through a personality set forth in the original source material she came from. The healthy man knows he is imagining his waifu, and accepts this.
Definition of lye. 1 : a strong alkaline liquor rich in potassium carbonate leached from wood ashes and used especially in making soap and for washing; broadly : a strong alkaline solution (as of sodium hydroxide or potassium hydroxide )
Noun. 1. caustic-any chemical substance that burns or destroys living tissue. chemical compound, compound - (chemistry) a substance formed by chemical union of two or more elements or ingredients in definite proportion by weight. lye-a strong solution of sodium or potassium hydroxide.