Limericks are a poetry style that follows the rhyme and meter of AABBA. If you want to write about ABBA, then let your 70s Swedish pop music muse take you there, Fernando. If not, there are plenty of things to write about, dirty or otherwise. Have fun with this. If you need help understanding the limerick, here is a website that features loony limericks:
We will also participate in our group therapy/poetry lesson.
See you then!