Is this an official Fritz the Cat shirt?

Nothing here confirms licensing. The film's characters are tied to Robert Crumb and the 1972 movie, so ask the seller about official licensing if that matters to you.

What does the bathtub scene print look like?

It reproduces the bathtub scene from the film. The exact size, placement and color of the print depend on the seller, so check the product images.

What is the shirt made of?

Most graphic tees of this kind are cotton or a cotton blend. The material is not specified here, so confirm fabric and care instructions with the seller.

No fit information is given. Graphic tees like this usually run true to size, but check the seller's measurements before ordering.

Is this shirt appropriate for everyday wear?

The film is adult animation and the scene is explicit in context. The print may draw attention, so it suits casual or fan settings more than formal ones.