Frodo raised a hand to lightly touch her back, both to signify to Coulson that she was indeed the 'lady friend' he'd gushed about spoken of, and to show off the fact that he could once again use his left arm.
Since he was off the pain medication, he ordered an fancy beer of the imported menu--something from Belgium--not to show off or anything, but because he liked wheat beers. Before the night was over, he might offer to pay for Coulson, since he still felt a bit like he was putting the man out. But now was not the time to discuss such things.