While it's technically possible to sleep on the Zoma Hybrid while it's expanding, it's not recommended. The mattress needs time to fully decompress and reach its intended shape and firmness level, which typically takes 4-6 hours but can take up to 24 hours for complete expansion.
For the best sleep experience and to ensure you're giving the mattress a fair trial, it's best to wait until it has fully expanded before sleeping on it.