Not really a pun though.
Consider the hackneyed pick up line "If I said you had a beautiful body would you hold it against me?".
To hold something against another is to bear a grudge. So he could be asking her if she minded him commenting on her body. An alternative is that he is asking her to press her body to his.
She cant tell his meaning, and he hopes to get her to laugh with his witty line and thus gain her favor.