These are NFTs offering an unlimited number of mints within a specified time frame. As opposed to limited editions, collectors can mint as much as they want within the specified time frame. And once this time elapses, the creators close the mint session.
Ape-ing (into something)
When you ‘ape into’ something, it means that you’re buying something in an irresponsible manner and typically out of “FOMO”, and/or without doing your due diligence.