Is there anything I can do or suggest to my bf that will help increase his volume of ?

Frankly I'm fine with his current levels of production, and until he mentioned it I had never really thought about it. Nevertheless, he has a few fantasies which involve him feeling more or less as if he's wielding a fire hose and as we enjoy helping one another realize our sensual dreams I thought I'd search for some fruitful info on the subject. Is there any sort of diet I can suggest to him or a technique that he or I can perform that will inspire "larger returns?"