If you’re nervous about girth issues with your partner, you can start with a very slim dildo and slowly work your way up to bigger and bigger dildos to get a sense of what size you can take. A flared base ensures that you’ll avoid a trip to the emergency room.
Your anal sphincters are surprisingly strong and can actually pull sex toys up into the rectum. If you’re using a toy, make sure that it has a flared base, meaning that the base is wider than the toy itself.