I would avoid any berlicka>crutch, unless there is a similar saying in English. The real meaning is, the loner takes the first opportunity (i.e. someone who may become his/her girl/boyfriend or a friend, depends on a context) as a rescue/salvation, clings to it even though such person is not worth it. "Berlička" can also mean a substitution for something real, e.g. when a weak person joins Jehova's Witnesses because he is unable to stand upright himself, and they give him the false "crutch"/support in life.