Because it is a special drink made for the gay, and since gay is such a popular word applied to things that people find undesirable, gayfuel can be similarly applied as an interesting alternative to "sucked ass", "lame" or "homo".
1. Did you see that horrible Australian Idol winner? She was totally gayfuel.
2. I totally screwed that exam up, I gayfueled it.
3. I'm going to gayfuel the match tonight, I'm so nervous.