As you spend time with your allies (either by doing missions with them or by spending time in the Party House), you will gain 'Friendship Points' with them. Your current amount of Friendship Points is visible from the main BvS page when you mouse over the avatar of the ally, as well as on the page for forming teams.
Each day, the players with the top 10 highest Friend Point totals for an ally at dayroll will be Hanging Out with that particular ally. (To see what yesterday's winning amounts were, you can check the Current Friend Rankings list.) However, in order to hang out you must have at least 1,000 Friend Points; otherwise you will not register as being in the top 10 for that ally.
After a hangout via Friend Points, your Friend Points with that ally will reset to 0. This will not happen if you hang out other ways (except, notably, Floating On Air).
While you are hanging out with an ally, you can learn their jutsu at half the normal XP cost. (This stacks with Eternal Mirrors for a total cost of 25%, if applicable.) In addition, certain special missions require you to hang out, or not hang out, with certain allies.
There are many ways to increase friendship points and hang out with allies:
Missions
On successfully completing a mission of any rank, you gain Friend Points for each of your active teammates:
- +45 points if you have three teammates
- +50 points if you have two teammates
- +55 points if you have only one teammates
Items
- Make-Out Mood Enhancer - If you only have one Ally in your team, Hang Out with them immediately.
- Silver Potion - +3000 Friend Points to an Ally if they are your only teammate
- Stuffed Walrus - If you only have one Teammate, Hang Out with them
- Rack on the Rocks - +5% Friend Points per 'Juice'
- Love Love Paradise - +100% Friendship Points
- Sad Robot - +50% Friend Points
Allies
Themes
- Floating On Air - Hang Out with all current Team members, but all Ryo and Ally Friend Points are set to 1
- Battle of Champions - +100% Friend Points on regular missions
- Emo Rock Ballad - Hang Out with Emosuke
- Funky Techno Grind - Hang Out with Stalkergirl
- Whiny Grrl 'Punk' - Hang Out with Pinky
- Good Night, Ninja - +1250 Friend Points to each teammate at the end of the day
Jutsu
- The Ninja-Mas Spirit - +100% Friend Points
- Running Man - +400% Friend Points with Girl Power team
- Perfect Girl Evolution: Loli Loli - -25 Stamina, +100% Party House Friend Points
Missions
- Find that Smell - +1500 Friend Points
- Deliver a Scout's Message! - +1500 Friend Points
- Hunt Down a Monster - +1500 Friend Points
- Sabotage Armor! - +1500 Friend Points
- Impersonate a Village Leader! - +4000 Friend Points
- Wrestle a Turkish Giant! - +4000 Friend Points
Others
- Mysterious Power Bloodline - If you aren't Hanging Out with anyone, you can Hang Out with 1 Ally of your choice!
- Party Room - Throw parties with your teammates to get Friend Points!
Removing Hang Out Bonus
- Awkward Silence - Unhangout with all Allies