i read an article once, probably in Marie Claire or some such magazine, about the rising trend of couples using viagra to spice up their sex lives. They both take it and it makes them horny. they intervierwed 3 different couples who use it regularly, the women were all really sceptical about it at first, they were all couples who just wanted to try something a bit different, or who felt they had lost their spark. None of them had any troubles with erectile dysfunction or anything like that. They all noticed a massive improvement, and said they had much better sex, that went on for longer. One couple actually ran into trouble because they became dependent on it, and found that when they had sex without the viagra ot wasn't as good, and in the end it destroyed their relationship.
Ann summers sell sometthing similar called "the original blue pill" which is meant to work like viagra, that you can just buy off the shelf.