OP takes penis up his ass. The thickest part of the BBC that fucks OP can be represented by a circular trace, pi * r^2. This trace is obviously in units of length squared (A = 1/2 b * h, b = 2pir, h = r). Now, how do we know for certain that this trace exists in the first place? The area around OP's prolapsed sphincter can be calculated using pi * r^2, which is the formula for area that we previously stated. If we let r = 7 inches, we see the area of OP's sphincter after he gets fucked by his boyfriend Rodney. Attach a Desmos slider from r = 7 to r = 12, you've got OP's sphincter on a typical Friday night.
tl;dr OP is a fucking faggot