In case you missed it, Nathan Fillion has adopted and is promoting a new catch phrase:

Ignore his clearly incorrect example sentence though, because Fangasmic is happy to offer you a selection of appropriate usages below.
- "Jesus christ, I'm so fucking sore!" "Why?" "Man, I got double rainbowed last night".
- Merlin's favourite sex act was the double rainbow, but he always made sure he had the next two days free before using it because of the serious medical side effects.
- All Brad wanted was for someone to bend him over and give him a good double rainbow.
Go forth, rainbow fans. You know you want to. Arthur certainly does.