Original Commentary
If I were Kimberly, I would has asked the sales man how much it would have cost for one of thoes underpants half mannequins. That would have look great under the tree and she could have passed it off for modern art.

Modern Commentary
This is why things things developed slowly between Brisbane and Kimberly. Movement must be reciprocal. Escalation must be simultaneous. The alternative is to become vulnerable if it is not reciprocated.
Gifts of lingerie are an escalation. There is an intimacy there that is not present in the gift of a juicer. There's an implied expectation of seeing the other person wearing that lingerie in the future. Thus, Kimberly must also escalate.
If she does not, things are in a tentative, uncertain state. So unless they are both acting at the same time, they are waiting for the other one to say it first, to paraphrase the title. - Terrence