Having sex with your sister. A Dundalk prom date can be distinguished from garden variety incest by the fact that you have to pay your sister in order for her to have sex with you. Also worth noting is that no one will ever mistakenly believe that you actually had a regular, normal prom date because no one in Dundalk completes the last two years of high school. Hence no one in Dundalk has ever been to a prom.
I had a Dundalk promdate this morning before I went to the methadone clinic.
I still owe her $10 for the Dundalk promdate.