As they say, Eva Mendes ... you're gonna need a bigger bag.

On the day reports swirled Eva and Ryan Gosling were expecting their second child, she was out running errands in L.A. and -- kinda foolishly -- trying to cover her baby bump with a tote bag. The couple's not confirming a pregnancy yet, but this pic says a lot.

Eva tried a similar tactic back in 2014 when she and Ryan were having their first kid.

That bag routine wouldn't work for most moms-to-be. Except for ... y'know.