What does this tweet say?
 

Bird crap fell on Shinji's car and he's been tweeting about it. Then there was this tweet which is hard to understand.

今さっきカミングアウトしましたよ？RT @saramao714: @shinji_sid 鳥のフンはどこについたんですか？

If you're not familiar with twitter then you might not know that this has to be read backwards, so this is the order to read it:

鳥のフンはどこについたんですか？
さっきカミングアウトしましたよ？

Is there some sort of joke about "coming out" being made here?

It's along the lines of:

Where did the bird poop land/arrive?

Didn't that come out a while back?

I don't think it's a "coming out" joke. He might be talking about how that topic has been talked about before??

shinji_sid
ソフトなトップにされてしまった鳥糞痕は洗車しても完 全に消えない…明日は焼き鳥決定だな(^-^)/

saramao714
@shinji_sid 鳥のフンはどこについたんですか？

shinji_sid
今さっきカミングアウトしましたよ？RT @saramao714: @shinji_sid 鳥のフンはどこについたんですか？


"ソフトなトップにされてしまった"
saramao714 was not able to understand the meaning of these words.
Hardtop - Wikipedia, the free encyclopedia
softtop(ソフトなトップ) = bird poop