What is the meaning of Flipside?

The reverse, in contrast to the obverse.

The B-side of a phonograph record.

A necessary consequence or corollary of something that acts as a negation or counterbalance; especially one seen as opposite, or as pro versus con.

The occasion when we meet again (e.g. when I return from work, etc.; said on parting); later or tomorrow.

Source: wiktionary.org