The aim of «ARIS» was to find a way to stiffen a surgically built penis (a so-called neophallus) so that active penetrative sex becomes possible, without requiring a further surgical procedure. Existing products are usually based on the anatomy of cis men. Their natural erectile tissue stiffens when it becomes engorged with blood. With a neophallus this can be dangerous, which makes a different solution necessary. In personal conversations with trans men who already have or are planning to have a neophallus, a list of requirements for the product was compiled. A survey was conducted and the clinical lead of gender variance at the University Hospital Basel was interviewed. The result is a sleeve which can be put around the neophallus, creating the necessary stiffness through its supporting elements. This product enables the wearer to have a confident sex life without being stigmatised. Owing to a new 3D printing process, «ARIS» can be manufactured from medical silicone and customised to meet individual requirements such as a specific circumference and length.