Prolonged eye contact isn't something that's going to bother Merrick overly but if he knew, well, surely he'd appreciate the effort she's going to. He'd also really appreciate it if she did not, in fact, chase him about. It might be play for her but it would give everyone else ideas.
The pooka reaches out to pat her hand once in acknowledgment of her promise before turn his back to the wall and his attention once more to the party. When one of the children in the room walk past without supervision, Merrick clucks his tongue at it loudly and frowns. The little being frowns back, drawing herself up to full height and fades back into the crowd.