[CrimsonKidCK]

A couple times I've had very slight bleeding on my behind, although I don't like that happening--but while those were fairly emphatic paddlings from my darling wife, I've endured more intensive ones without my skin being broken.

I did end up with bluish bruising from one quite extensive OTK spanking with a wooden hairbrush, although it was only on one buttcheek (the left one IIRC), and it hadn't been smacked any longer or harder than its counterpart, which was merely a moderate magenta in color--nor did the mildly bruised cheek hurt any more (immediately or for the next couple days) than the right one.

So AFAIC it's hard to determine what will or won't cause slight bleeding or mild bruising--although IME (very limited) using a hard, flat implement with a small striking surface relative to its weight could result in bruising... --C.K.