I, like Got RPM, can't believe the quote in the first post. With all the information & discussions on all the forums out there, who still stores their Lipos fully charged? That's a recipe for disaster.
As stated above 3.8 V is the nominal storage voltage.
Lipos can puff if stored fully charged for extended periods.
Lipos do not need to be cycled. That just reduces the life of the cells that little bit more each time.

ANILAO.
If you have packs fully charged that you are not going to use in the next couple of days. Use the STORAGE mode on your charger if it has one, or set the DISCHARGE mode to 3.8V & discharge the pack that way.

All the best.
Paul.