A good first choice begins with comfort, material safety, and an honest idea of the sensation you are looking for.
Begin with your comfort zone
For a first purchase, moderate dimensions and a smooth silhouette can make learning easier. Consider both length and width, and leave room to build confidence gradually.
Choose body-safe materials
Non-porous, body-safe silicone is easy to clean and works well for many people. Always follow the care guidance for the particular material and use compatible lubricant.
Details that make a difference
A flared base supports safer anal use. A stable suction cup, flexible neck, or textured finish can be useful features when they match your intended use.