Rollin' with the Homies
Inga is Frederick Frankenstein's lab assistant. To borrow a question from Elizabeth, "Excuse me, darling. What is it exactly that you do do?" Well, she wears skimpy clothes, administers sedatives to the monster, and is really bad at charades. And she introduces the word of the day: schwanstucker. She looks like an innocent, naïve country girl who's totally unaware of her seductiveness.
Her main job, however, would have to be the double entendre. Inga has some of the film's best lines, like the classic;
INGA [actually rolling in hay]: Vould you like have to a roll in ze hay?
And, responding to the Doctor's comment about door knockers with surprised flattery.
Eventually, she and the Doctor do have a roll in the hay that doesn't involve much hay, after she offers to "relieve this torture you are going through" with an "intellectual discussion." Every doctor needs a good assistant, so it's not surprising that Frederick ends up marrying Inga instead of Elizabeth at the end. Now they can have intellectual discussions any time they want.