しりうま
buttocks of a horse being ridden or followed; blindly following suit
Also written しり馬
Noun
人ひとの尻馬しりうまなどに乗のるな。
Don't follow anybody blindly.
自民党じみんとうが小泉人気にんきの尻馬しりうまに乗のった。
The LDP rode on the wave of Koizumi's popularity.