Whether or not someone engages in masturbation is basically impossible to accurately judge based on appearance, eyes, complexion, etc.😂

Many online claims are just guesses, such as dark circles, acne, lack of energy—these are all related to sleep, stress, and diet, and don't indicate anything
If we're being honest, there are only two direct ways
One is if the other person tells you themselves
Another is if you're very close and can roughly sense it from their life habits
Apart from that, trying to judge through observation is basically unreliable