QUOTE(Mx4_1204 @ Feb 24 2020, 23:06)
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Purple and blue are both ブボ, with emphasis on different syllables. Purple is ブッボ (bubbo), while blue is ブボオ (buboo). Orange, similarly, is ブッ (buh).
Not an expert on sfx, but my guess is they're all gagging noises from the ejaculation. Note that they continue in the second panel.
The red one is a bit complicated. "一昨日のほう見て" literally is "looking at the other day", but it's closer to "based on the other day". "フェラしてんの?" is something like "You've never given a blow job?". The exact translation would need some context to finish, but my rough translation would be "Wasn't it just the other day that you said that you've never given a blow job?".
Not 100% sure on that one, but it might give you a better idea on what to put.
Green is easy. "That's enough!"
I'm going to have to disagree with your translation on red bubble. "フェラしてんの"="フェラしてるの" and it's just "fellating" or "blowing," and I highly doubt that "based on the other day" is a fitting interpretation in this case.
"一昨日" means "day before yesterday" and japanese make ridiculous sentences as a sarcasm/mockery.
For example "Come back day before yesterday(which is impossible)" can be used to say "don't come back ever again."
In this case, direct translation of red sentence would be "Why are you looking at day before yesterday when you're giving me a blowjob," which can be interpretted as "what the fuck are you looking at while giving me a blowjob?" or "why are you looking away while giving me a blowjob?"