Yeah, I've partaken on several trips. I am Portuguese, so that's an obvious advantage. If you don't speak the language, you can still find some fun, but chances are you'll pay a bit more. The scene is widespread and any town of size will have some working girls. Quality is not great, but then again, I've never shared the love for Brazilian working girls that so many seem to have.
Your options,
Correio da manha is a daily tabloid, they have ads,
http://www.conviviocm.pt/list_anuncios.aspx?N_ANUN=227
Street walker in Lisbon around the Poco do borretem, lots of east european (romanian) girls. Area can be rough, don't chance it unless you enjoy risk
sex clubs, elephante branco, Night and Day....these places are almost straight pay for play. Lots of Brazilian girls charging 300 E and up. Wear dress pants and a blazer or you won't be let in. No jeans, shorts, sandals etc.
