Pillsbury Doughboy

Poppin' Fresh, more widely known as the Pillsbury Doughboy, is an advertising icon and mascot of the Pillsbury Company, appearing in many of their commercials. Many commercials from 1965 until 2004 (returned in 2009 to 2011 and 2013 in a Geico Commercial) conclude with a human finger poking the Doughboy's stomach. 
The Doughboy responds by rubbing his stomach and giggling ("Hoo-Hoo"!, or earlier on, a slight giggle "hee hee").