How to avoid oscillations when NVT used

Dear Lammps users
I have a simulation system. There is a graphite pore, and a graphene above it covering the pore. The DRIP and REBO pair style were used. I looked forward to the graphene’s center area sinking slightly. But as NVT used, the graphene oscillated up and down. Do you have any suggestions to make the graphene’s center area sinking slightly without oscillation, meanwhile keeping room temperature.

Sincerely