His own arms are quivering from the effort to keep Merrick aloft and also work him open, one arm doing most of the heavy lifting on its own. The rest of his body is tense from restraint and it very nearly all comes crashing down the instant Merrick says now.

Metaari somehow manages to keep it reined in for a few moments longer, enough for him to empty to rest of the vial onto himself to slick it up. Once he feels he's ready he shifts his position, widening his stance a bit as he guides himself toward Merrick's entrance. His head brushes against him, searching, until he finally finds what he's looking for and he starts to slowly--agonizingly--press up.