two-step option selection

I need to configure an option where if selected, the price changes to whatever is specified in the modifier AND then (and only then) the customer is asked for text input.

This doesn’t seem to be possible in one elegant “go”, any ideas?

Suppose you’re selling a T-shirt and for $2 extra you can customize it with your name. You select $2 for the option and below you get a place where you can add your name.

I see where you I can add the option for $2 and in another option I can have a text input, but no easy way to combine the two options. What I’m trying to prevent is people NOT selecting the $2 and still adding their name, which would create confusion for those who manage orders.