When charting your BBT

Ashley
Do you have to use a certain thermometer or will a regular one work? & what's the best method to read your temp? Orally, vaginally or in the mouth? I've ready people do it all different just as long as your logging it first thing in the morning before you get out of bed. I know if we made it this cycle its too late to detect. But, I think j want to get in the habit of doing it in case this wasn't our month. Also, what are the typical temp patterns? I know you need to get your cover like first to know where your body usually runs at then you'll know when your temp is dipping or spiking. But is there anything else I need to know? Thanks in advance ladies!