Somewhat odd to have used OJ as the mixer; vitamin-C is often considered to accelerate the breakdown of psychoactive substances (especially those like MDMA and LSD), so would normally be avoided until you feel you're 'done' and want things to end.
Anyway, it doesn't follow that faster breakdown makes the trip end... could be that the very process of breaking down the active substance produces the effects desired, and the vitamin-C acts as a catalyst to "even out" the experience.
Actually, it does mention orange juice as containing flavonoids which may have some (albeit lesser) effect on drug metabolism.
I'm not sure if/how that translates to other drugs like Psilocybin, but it does raise some interesting questions. Do you by any chance have a source regarding the original "enhances the experience" statement? (for my own curiosity really - I'm not saying that you're wrong or misinformed)
[1] http://books.google.com/books?id=_m7gPani5D4C&lpg=PA124&...
HTH
Now, if you grind the mushrooms up and let them site in lemon juice for 30+ minutes. That will definitely accelerate the time you reach the peak of the trip. The acids in the lemon juice break down the mushrooms so the stomach can digest them more quickly.