When "Grandmother" shrunks Erik, his clothes doesn't join to shrunk. When Erik appears he is naked.
Another scenes (in snail hotel) Erik takes a shower, or only takes off his top-of-pajamas.
The bee wants to know if Erik is also an insect. Erik claims his penis would be his sting. Thus he shows his penis for the bee while he looks away in disgust.
But in no scene a penis or buttocks is ever straight shown.