A pack-and-play dildo is both a sex toy and a prosthetic device. It serves the dual purpose of acting as a packer - a soft, penis-shaped mold (usually made from silicone or cyber skin) used to create the appearance of a “bulge” in someone’s pants, and a dildo - a penis-shaped toy that is firmer and used for penetration of a partner.
More About Pack-and-Play Dildo
This toy is often used by someone who is trans masculine, genderqueer, or gender-non conforming but can be used by anyone of any gender identity or body who wants to create the appearance of a bulge or participate in strap-on play. People often choose this toy over a separate packer and dildo for convenience and cost efficiency. Instead of having to change out one toy for the next when engaging in sexual play, this one is ready for action at any given moment.
Fun fact: The term "packing-hard" is often used to refer to wearing a pack-and-play dildo instead of a soft packer.