NO GUARANTEE here but supposedly this will increase fuel efficiency up to 35%. More info is here. Naturally you really check this out before trying.

OMFG it looks like we're all going to have to go back to the days of driving a girl to a remote spot and telling her to "put out or get out" in order to get laid. Shrinks say that at least fifty percent of women don't like sex at all, but now it looks like it will go to ninety percent. Women are now likely to be totally disinterested in fucking if they are taking the pill. Hey, that's why God invented guns ain't it? A return to real masculinity is at hand. "Hey bitch. Where to you want it, heads or tails?"