I live in Santa Cruz, Madeira, which is particularly known among the island villages for this specific form of traditional entertainment. While "despique" may be a part of many of the local feast day celebrations, Santa Cruz holds an event specifically dedicated to this. Contestants "face off" to the tune of guitars, "braguinhas" (which Madeirans took with them to Hawaii and gave origin to the ukulele), accordions and percussion instruments. One contestant begins by improvising a rhyming verse...generally of four lines...the opponent must come back with his response in four lines of improvisation...and this can go on for a long time. Participants are judged by their ability to improvise, and of course, the sharper and more cutting a reply is, the better. The subject matter can become somewhat "picante".

I don't know of a standard translation for this. In the site from which the following passage is taken, I notice that the particular line referrring to the "despique" is omitted in the corresponding English page of the site. Note: There are also numerous errors in the English, including the misspelling of "braguinha"... for the record, although I have translated many hundreds of pages of tourist-related material for the Tourist Office and private clients, this site is not my work. :-)


Diga-se no entanto, que há uma tentativa para preservar e perpetuar certas características tradicionais, como por exemplo, o "bailinho" com o acompanhamento de vozes e música, e o conhecido "despique" (ou seja, quadras soltas improvisadas por dois cantores alternadamente), oferecidos pelos ditos grupos folclóricos aos turistas, são um autentico folclore insular.
http://www.tourmadeira.com/pt/pag_29.php

I would leave the original and give a brief explanation in parentheses: it's actually a form of verbal sparring and besides sexual innuendos, can include political and social satire.