From Masq

Mortal/Mortal+ are able to soak both bashing and lethal damage.

Mortal/Mortal+ characters cannot be bonded without their OOC consent, mortal/+ staff consent, and vampire staff consent. Even once all these consents are gathered, they cannot be bound beyond a level 2 on the blood bond scale.

Please note that this is only in regards to Mortal/Mortal+ characters being bonded only. Once you become a ghoul, you move into the Vampire Sphere, and are subject to the normal rules for ghouls and blood bonds.