A "Double Blowie" is not a standard or widely recognized term in English, and it might be a bit of a tongue-in-cheek or humorous expression. Breaking it down:

• Blowie could be a slang or playful variant of "blow" or "blow job," which is a colloquial term for fellatio.
• Double implies something is done twice or in two ways.

So, putting it together, a "Double Blowie" could be a humorous or informal way of referring to someone (typically a male) receiving two forms or instances of oral attention from two different people (often interpreted as two women). It is usually used in a light-hearted or joking manner, especially in casual, male-centric contexts.

It's not a formal term and is likely to be used in specific social or cultural circles, particularly among those with a sense of humor about such things.