The alternative splice event of a NAGNAG acceptor or a GYNGYN donor can affect the UTR (untranslated region) or the coding sequence.
In the coding sequence, the respective intron can be either in intron phase 0 (intron position between two codons), in intron phase 1 (intron position between the first and second codon base) or in intron phase 2 (intron position between the second and third codon base).

Here, you can restrict the search to those NAGNAGs / GYNGYNs in introns that are located in the 5'/3' UTR or in specific intron phases.