You have mastered the ways of the whip and the intricacies of such an exotic weapon. You gain the following benefits

• When you hit with a melee attack using a whip you deal an additional 1d4 damage of whatever type the whip deals.
• While you are wielding a whip, other creatures provoke an opportunity attack from you when they enter your reach.
• You are able to use the whip to keep your enemies close and your buddies closer. As a action, you can use the whip to restrain a creature within the whip's range. You can not do this action after you've already done an attack. A large creature or smaller must make a acrobatics check against a DC equal to 8 + your Proficiency Bonus + your Dexterity or Strength Modifier (Your choice), or be Restrained until the start of your next turn. You can not attack with the whip while being used in this way.