Question

to foul your own nest - If you do that you'll only be fouling your own nest.  - Yes, we all like the comforts of modern life, but we don't seem to realize that we are fouling our own nest. Pollution has never been more of a problem than it is today.  - My father was just moral enough to avoid fouling his own nest by fooling around with her with me on the premises.

Accepted Answer

to do something that makes your own life unpleasant or difficult

Idiom	to foul your own nest
Definition	to do something that makes your own life unpleasant or difficult
Examples	- If you do that you'll only be fouling your own nest. - Yes, we all like the comforts of modern life, but we don't seem to realize that we are fouling our own nest. Pollution has never been more of a problem than it is today. - My father was just moral enough to avoid fouling his own nest by fooling around with her with me on the premises.

Fouling Nest Foul Makes Life Unpleasant Difficult Comforts