How do you cook toor dal without pressure cooker?

the best way to keep anything from foaming in a pressure cooker is to add 3 or 4 drops of cooking oil.

However, toor dal is also known as pigeon peas which most commonly come canned, in the U.S. so there is really no need unless you want to start from dried beans just because.

You should always rinse dried toor daal 2 -3 times with water. Once you stop seeing whitish liquid after wash cook it in a pressure cooker. It should get cooked without foaming.