I had a discussion with someone who holds that there is a heter for engaging in shichvas zera levatala for the case he cannot fall asleep, ie it helps him falling asleep. He claims he is in a situation of oness, therefore he is not chaiav…thank you for your help
This is incorrect. Wasting seed is a Biblical prohibition, and according to the Zohar the most stringent of all. Stress is never a reason to permit sinning of any kind and surely not this sin. Generally, we only permit committing a Biblical transgression in an in stance where there is danger to human life [pikuach nefesh].