Checking with a stack of chips in your hand

[Jive Dadson]

You could be really cool and yell out, "That's a string check!"

But seriously folks. If it's not changing the action, it's probably best not to tap the glass. If his left hand opponent ever folds with no action to him, or bets and says, "Call," or tries to raise the check, then the dealer will probably say something. If not, reassess your options.

[Mygtar]

Someone should have been paying attention, instead of being a "Chatty Cathy".