For layers it’s easier to build them all, then fuse them one in one go, though a lot of pieces go into the kiln a few times. So long as you dam things up well, and heat with the right schedule they don’t flow. You can flow a printed piece too to get a melting print effect, but you have very limited control, so it’s hard to do well.
Yes, slumping is the term for softening things to get them to either drop a bit (or a lot) into a mold. A lot of printed pieces people do get slumped into curved forms, since they stand better unless you’re working really thick - thick pieces are my faves, but they can take days to anneal and there’s more room for a mistake to leave you with broken scrap. Putting something in a kiln and checking back in a few days to see if it worked takes some patience too.
