Phallic erection symbolizes the fertile nature, a power that wishes to create a new world. This is the reason why many phallic statuettes were dedicated to Spring, as a season when people get the power of fertility from the gods.

{Iamblichus, About Mysteries 11}

The phallic erection was more than fun and carnality: it was a brain erection to arise all inner soul functions, we would say it was an uplifting for the soul. This uplifting is actually a return to the Divine source. As for the baccheia (Bacchic dance), it is actually a divine inspiration, a possession, an infinite spiral dance to reach the Divine.

{Proclus «Commentary on Plato’s Republic, 1.181.23 – 1.181.27}