RNA splicing and editing contribute to functional diversification of proteins encoded by single genes. Previous and current research primarily focus on sequencing of bulk material and bioinformatics to identify editing and splice sites, but these technologies ignore by nature the role of individual cell types in the regulation of RNA splicing and editing. We present new molecular tools for analysis of RNA splicing at single cell resolution using synthetic and natural introns. We show that cryptic splice site usage is not that rare than assumed previously, because the results identify consensus sequence motifs involved in effective cryptic RNA splicing. Furthermore, cellular heterogeneity of cryptic splice site usage demonstrates cellular regulation of this type of RNA processing and may reveal a novel dimension of cellular regulation by RNA processing and vice versa.