OH NOOOOO! My babies a thumb sucker! At 4 months she has taught herself to suck her thumb when she's upset. So mainly this happens at nap time, or when I have to ignore her ie. making dinner, having slimy hands and such. But being an uncoordinated baby she holds her right hand in a tight death grip so there's no escaping her mouth. Got her out of bed last night for her late bottle and she had her thumb in her mouth till I pried in out to replace it with the bottle. So awesome.