When you use FeedBlitz forms, you can optionally set up additional fields on the form so that a visitor must select a choice to expressly give consent prior to the dual opt-in process starting.
Log into your FeedBlitz account.
Select your list.
Click the I want to button
Click Subscription forms & links.
Select your form.
Drag the GDPR Radio item into place.
Edit the prompt
Edit the choices
Scroll down and save the form.
Click Code. Select the style of form you want. Copy the code to use on your site.
A pdf of step-by-step screenshots is available here.
We also believe that you do NOT need to provide an extra confirmation checkbox when a form is clearly used for the purposes of creating an email subscription. You may want to add text that says something like "By clicking the subscribe button you agree to receive email updates from us".
You DO need to provide a consent control when the subscription is not obvious or part of another offer.