I will give a pedestrian introduction to the paradigm of string fragmentation in QCD, including some unique topological structures, called string junctions. These have gained interest in recent years, as dynamical models of string junctions have predicted order-of-magnitude effects in heavy-flavour baryons at low pT, which agree with recent LHC measurements.  In previous theoretical work, however, the limit of a low-pT heavy quark was not well defined. We reconsider what the string equations of motion imply for junction systems in this limit, and find that the junction effectively becomes bound to the heavy quark, a scenario  we refer to as a pearl on a string. We extend string-junction fragmentation in PYTHIA with a dedicated modelling of this limit for both light- and heavy-quark `pearls', and confront the updated model with the observational evidence.