Well, that seems right, but allow me to clarify.

To use the food analogy, masturbation is like subsisting on flavorless but nutritionally adequate food, the proverbial "bread and water." Sex with someone who finds you desirable is more like that rich, delicious dessert that advertisers hope you've been fantasizing about recently. (Note the with someone who finds you desirable. It's important.)

If we have to use the drug metaphor, masturbation is more like giving a heroin addict all the methadone he wants.