If you do speak portuguese or spanish it is helpful, but anyway you will go along easier in Portugal then in Spain if you only talk english. Lisbon is a wonderful town, people are friendly, sex available 24 hours a day.
Crime rate is low and with an exception for cab drivers the risk of being cheated can be ignored.
At two discoteques in Lisbon you will be able to find the most wonderful looking girls. One is called Hipopotamo, the other Elefante Branco. They are both open from 8pm, but action starts around 9,30pm. For 60-80 dollars you pick up a wonderful girl for the night. She might ask you for more but it is always negotiable.