For any irreducible representation of a surface group into \mathrm{SL}_{2}(\mathbb{C}) , we show that there exists a pants decomposition where the restriction to any pair of pants is irreducible and where no curve of the decomposition is sent to a trace \pm 2 element. We prove a similar property for \mathrm{SO}_{3} -representations. We also investigate the type of pants decomposition that can occur in this setting for a given representation. This result was announced by Detcherry and Santharoubane (2022), motivated by the study of the Azumaya locus of the skein algebra of surfaces at roots of unity.