hollow body with diametrically opposed retaining clips 15 on its outer wall the outer wall can be rigid and the inner wall flexible both walls can be flexible as well after inflating the double walled cylindrical fixing means with at least a flexible inner wall the inner diameter is reduced and the inner wall evenly and flexibly tightens along the entire perimeter of the penis in yet another variant not shown in the figure an elastic bulge surrounding the fixing means fully or partially can be attached to the distal rim of the respective fixing means to optimize fastening in axial direction a preferred embodiment of a substantially circular cylindrical fixing means 3 that fully and flexibly surrounds the penis with retaining clips 15 offset in stretching direction is shown in fig4 and 5 the fixing means 3 in this embodiment consists of two shells 23 a 23 b connected by a hinge 20 and a lock 21 in the embodiment according to fig4 an inflatable air cushion ring 24 split in the area of the lock 21 and equipped with valves 19 on its outside to supply and discharge air is attached to the inner surfaces of shells 23 a 23 b according to the variant shown in fig5 an elastic gel or foam lining 22 is applied to the inner surfaces of the two rigid shells 23 a 23 b and broken in the lock section so that the upper shell 23 a can completely be swiveled away from the lower shell 23 b shells 23 a 23 b differ in size and the retaining clips 15 are attached at an upward offset in stretching direction to the bigger shell 23 b the lock 21 can be.