We're not gonna lie, one of the best fill-in-the-blanks here is, "I love your you-know-what" (or whatever word you can say without laughing or blushing too much。) Men want to know that you're attracted to what they have。
不是让你去撒谎，最适合填空的话就是：“我喜欢你的某某地方”(或者任何讲起来自己不会发笑和脸红，比较靠谱的赞美话)。男人都想知道自己什么地方吸引人。