The best time to contact Dionysus is at full moon, especially in the Spring. When it seems that the universe has gone bonkers & common sense has flown out the window, Dionysus is around. If you're female & your hormones are running amok, you could use the mood swings & sharpened emotions to your advantage. A few glasses of red wine wouldn't hurt either in contacting him, as he is a god of alcoholic revelry. If you're not a drinker, wait till you get to that point of "divine high" in your meditative state. A rural setting (like Pan) is also a good idea, but unlike Pan, you can tap into Dionysus in an urban area, as the key is excess & excitement.