Of course they were. Because neither of them liked to lose though Natsu likely fed that characteristic inside of Lucy since becoming her partner and even more so after becoming her lover. He could feel her growing hotter with each brush of his fingers while also realizing where he could get the strongest reaction.

Which all came apart when he let out that rumbling growl when her hand moved closer to his own heat. She could keep up with him yes. And he wanted her to.