But why do you want to disable it ?
It increases the security of your account.
When you activate it, you can flag the checkbox "remember me for 30 days" (or similar,I do not remember exactly) without any problems.
It is very important NOT to delete cookies for MalwareTips otherwise whenever you access, you must make the two step verification.
Anyway to disable it, put the mouse pointer on the name of your account at the top right and in the menu that appears click on "two step verification", put your password and follow the steps.