That little whine makes him almost want to give in and let Ianto come, it's so pitiful, but he manages to resist. Ianto's been so firmly into this whole denial thing, it would be tragic to let him fail now.
So he grins when Ianto himself comes up with an even better solution. "We did," he agrees, rather delighted, and adds with a quirk of an eyebrow, "I think it would fit me, too, you know - if that was something you'd like to try too at some point?"