Squeezing a lemon wedge over a tablespoon measurer can be difficult and inexact. There's gotta be a better way!
For small citrus fruits, enter: the citrus juicer + collector. This product is one of my most frequently used kitchen tools. Cut a lemon or lime in half, squeeze it around the juicer, and the juice falls into a measured container. Strains the seeds, keeps the juice. And it's only $6.
You can buy my favorite one, here: https://www.crateandbarrel.com/mini-citrus-juicer/s220805
For larger citrus fruits, use a citrus reamer (also called citrus juicers) over a bowl. They often come in metal or wood, and all you have to do is twist the pointy end into the cut fruit. Far more efficient to use when collecting grapefruit or orange juice, with much less food waste.
OXO is one of my favorite brands, try their wooden reamer here for $6, here: https://www.amazon.com/OXO-Good-Grips-Wooden-Reamer/dp/B0007VO0DA