Kidnapped hippo ladies

Six hippos have been kidnapped, stripped to their panties and slipped in a snug long crate.
Their hands and feet bound together by industrial tape used to fix machinaries.
Their mouth filled with expanding foam and their lips and jaws sealed together by a cross of the same tape.
They can't avoid blushing in shame and disconfort as their struggle make them rub their breasts and their butts against each other.
They try to scream for help but their merciless gags wont let any sound escape from their throat.