How do you pronounce a ッ followed by a ー?

Question

I thought I fully understood katakana, but an old meme confuses me.

Here is a nicovideo dictionary entry on it: フタエノキワミ、アッー!

If you listen to a video of the English voice actor saying it, it just sounds like a normal "aaaaaa" which I would expect to be アー. I know アッ is already "ah", but elongating that seems impossible to me. Why isn't it something like アーーッ? Maybe I'm overthinking this because it's a meme, but this spelling was agreed on, so there's clearly some construct to the language that makes this normal.

Answer 1

Good point. It's actually unpossible.

「アッ」と発声した後息を溜める所作を表現したものと思われるが、「ッ」の後に「ー」が続くという発声の不可能性からネットミームとしてウケ、やがて同性愛関係で「ア」のつく発声を表記する際に多用されるようになった。 (source)

While supposed to be transcription of a gasp after uttering アッ, its impossibility of vocalization, that a ー follows a ッ, has made it viral as an internet meme, eventually becoming a popular way to transcribe ア sound in (typically the end of) a phrase with a homosexual innuendo.

And the article is also kind enough to provide a pronunciation guide:

文法上発音することは不可能だが、声に出して朗読する際は「アーッ！」で代用することが多く、この単語を面白がる人達は「多田野選手のみ発音ができる」とすることがある。
英語ではその使われ方から"aargh!"［ɑːr］という発音が一番近いと思われる。

Although grammatically unpronounceable, it is usually read out as if アーッ！, or those who enjoy this word sometimes claim that only 多田野選手 (the meme origin) can pronounce it.
In English, "aargh!"［ɑːr］might be the closest pronunciation judging from its usage.