I totally agree with you. For years, I felt totally inadequate about sucking other guy's cocks. I felt like my mouth was too small and was afraid of scraping my teeth against their cocks. It has happened to me me before when getting sucked by guys who just weren't good at sucking cock.
My cock is small to average in size so when I felt someone using their teeth, I would usually try to pull out and maybe take care of myself. I wanted to become better at sucking so I started seeking other guys who were small to average in size and uncut. I quickly found out that if they were uncut and their skin was loose, it was easy to suck that person and they would often leave being happy and fulfill.
As I became more comfortable with sucking guys cocks, I became able to suck on larger cocks. I started learning how to start slower and gently try to get their cocks down my throat. Soon it was becoming easier to swallow a guy's cock and to allow you to suck other's guys cock to completion.
It felt so good that nowadays I prefer sucking over getting sucked or penetrating the guy or trying to get penetration.