Puns or clever worldplay in Ayu lyrics?

[Ayu_no_tenshi]

in Sparkle...she says 'いつまでそこでそうやって指をくわえてるつもり？'　(itsu made soko de sou yatte yubi wo kuwaeteru tsumori? / how long do you intend on standing there with your finger in your mouth like that?). '指をくわえる' (yubi wo kuwaeru) literally means "to hold your finger in your mouth" but is an idiom that has a meaning along the lines of 'thinking about something enviously but doing nothing about it'.