Goliath, Angela, Elisa, and Bronx went back to Avalon numerous times during their World Tour. Angela would generally be the one to use the spell (and after some time, both Goliath and Elisa were able to do so as well, though Goliath is the only one confirmed to have cast it).  It is also believed Angela taught it to Jade. 
Using this spell, Avalon could be accessed from any body of water. It is a powerful spell that does not require a conduit.  Even non-sorcerers (like Tom and Goliath) were able to cast the spell. 
- Vocate venti fortunate,
- Ex ricae Oberonis,
- Et hic navis frugum regate,
- Ad orae Avalonis.