MEL stands for Minimum Equipment List. It is usually a very large book in the cockpit that contains a list of things that can be broke and still dispatch the plane.

When something breaks, maintenance looks it up to see if must be fixed or can be "deferred by MEL". If they don't have to fix it, it is listed as inop on the FP/R (Flight Plan/Release), by MEL #. Sometimes MEL's have certain operational restrictions that must be followed. Sometimes there are limits on when they must be fixed.

I think he is saying that "viagra is required for dispatch", ie, every pilot must carry it on a trip. All I can say is, "why carry it if you don't need it?"