If you want to compare, the original text seems to be:>[ウェブエッセンス] コスプレウィッグ とある科学の超電磁砲 食蜂 操祈（しょくほう みさき） 風 高品質wig コスプレ ウィッグ＋ウィッグ専用ネット＋ オリジナル ブレスレット 付き>>16026
"x" is sometimes used to indicate small kana (sutegana), hence "uxebuessensu" for ウェブエッセンス (Web Essence, xe = ェ, uxe = ウェ = we) and "kosupureuxiggu" for コスプレウィッグ (cosplay wig, xi = ィ, uxi = ウィ = wi). Typing "xyokuhou" gets you ょくほう. I don't know why the initial し isn't represented in the translation.>>16027
In Chinese pinyin, "x" represents the same sound as Japanese "sh", but I suspect that that isn't why we're seeing it here, see above.
As for Tsuki/Tuki, it depends on the purpose of the romanization. If the purpose is to represent the kana, using "tuki" for ツキ and "toxuki" for トゥキ might make more sense. If the purpose is to represent the pronunciation, then using "tsuki" for ツキ and "tuki" for トゥキ makes more sense.>>16010>also I wanted to just post this in the blog thread, but I can never find it anymore.>>>/qa/65922