A human (or mage), at any point can be infected with ghoulification. He she or it do not need to ingest the blood, merely making sure the blood travels into their system will be enough of an infection.
The vitae is very addictive, way more than anything else (such as heroin, tobacco) and you need to roleplay that, because otherwise resisting the call of the blood would essentially make your character an awfully moody person, each day the less blood you get will make you more angry and craving for blood.
Level of blood bond as follows:
One sip - Nothing too significant, the victim feels a friendly relationship, and they're certain they knew this person. To resist this level of blood bond you need a roll of willpower (dice can work rly) and to get more than 3.
Second sip - The victim feels brotherhood, they will look at the vampire in a form of a brother or sister, they will seek guidance and tend to ask them for help. To resist this level of blood bond you need a roll of willpower and to get 5.
Third sip - She feels passionate, she feels love and emotion for the vampire, she'll never let him go and will most likely never plot against her master. To resist this level of blood bond you need a roll of willpower and to get 6.
You need to agree OOC in order to become a ghoul, you cannot be forced.
Before you accept, make sure you know how they work, when you do become ghoulified, you stop feeling threatened by the presence of your master, you love him and never plot against him unless you can do a willpower roll, it is almost impossible to resist the curse without using willpower and not recommended, as craving for blood can be dangerous.