From Longman Dictionary of Contemporary Englishget off on something phrasal verb informalEXCITEDto become excited by something, especially sexually excited → get→ See Verb table
Examples from the Corpus
get off on • I expect SHe hardly gets off on this stuff.• Clive thought she might be a rare type of pervert who gets off on vociferously condemning all the vices she actually practises.• If everybody was just gon na get off on weird sounds, there'd be no words. 