A very fancy name- POIS. Need to know more about the symptoms suffered by the person post orgasm.
And masturbation never needs treatment (many quacks do it though).
What at times need to be treated is post masturbatory guilt and anxiety around this natural and completely harmless activity.
Next Steps
Consult a qualified psychiatrist to get rid of many possible sexual myths he/she must be harbouring.
Health Tips
Do not self medicate(? SSRIS with naltrexone), and avoid quacks