That was metonymic for "coming up with some excuse which resulted in me paying for both of us". I don't remember now where he said he didn't have his wallet, said he had it but had no cash, or what. It amounts to the same and it's the reason I haven't invited him out again.

(Actually it's even worse since I'd already taken him out to dinner once. He doesn't "owe" me for that, since it was my treat, but it would've been comme il faut for him to return the gesture, even if it was only pasta with can sauce at his place.)