A multi-IV set retention device for retaining flexible lines (e.g., medical fluid lines, such as IV sets) comprises a retention body having a normal axis, and a plurality of retention slots that removably receive and retain flexible lines, and a plurality of openings to facilitate insertion of a flexible line into an associated retention slot. The retention slots are radially arrayed about the normal axis of the retention body, such that the plurality of flexible lines is movable as a unitary body. The flexible lines can be radially bundled as a collection of flexible lines that define a center of mass about a central portion of the retention device, so that the flexible lines move and act as a single flexible line. One or more of such multi-IV set retention devices can be coupled along a length of one or more flexible lines, thus fanning an IV set retention system. A method of making the multi-IV set retention device, and a method of retaining flexible lines, is provided.
