Getting diff measurements for my penis size

so I’m curved left and up so it’s kinda hard to measure but when I measured side to side with my phone on liek the same line as it would be drone the base it was the same lenght of my phone but when I measured with a string I got like 5-5.5 or sum like that but I use a diff string and got like 7 I measured it beside a spray can and got like 6.5 idk what to do how can I mesure it right btw I have a tape measure