1) To act in an inapropos or unfitting manner, especially when the situation calls for formality.
2) To force oneself in a social situation foolishly, making an ass hat out of himself or herself.
(At the Governor's Mansion)
Aristocrat 1: "That gentleman behind me just spoke of this burning itch in his nether-regions, and subsequently pulled out his genitalia to show us his herpes scars.
Aristocrat 2: "What an asshat. He sure put his dick in a teacup!"