Но она тут же села ему на шею - как и всем своим бывшим парням.
This is part of an IM I received from my girlfriend, in which she was talking jokingly about her female friend bordering on control freak vis-à-vis her henpecked boyfriend seemingly at her beck and call.
In Japanese, there is an expression 尻に敷かれる, literally "a man is beneath the hips of his wife/girlfriend", albeit without specifying which part of his body she sits on. I wonder if this Russian expression is more or less the neck version of it?
Is the phrase "тут же / immediately" part of this idiom?