LOL I found myself yelling at my pair of White Orpingtons (siblings) this morning. "Derek be nice to your sister! No, no, you're doing it all wrong! Watch your brother, he knows how to do it!" He always grabs the back of her head from the front, holds her there, squats and breeds the ground. *shakes head* His Silver-laced brother has no problems breeding the pullets he's in with. lol
But back to the original question, inbreeding is alright to do. But always remember faults just like good traits can be strengthened and fixed through inbreeding. So if you have an aggressive male, or side sprigs on a comb just remember breeding two birds that are related, sharing the same genes, means those traits will be more likely to be passed on to their offspring.