How to unlock all characters: (Use - Settings - Unlocks) 
1: Rainbow Dash - Pump: Off Vibrator: Fast - (Unlocks Pinkie) 
2: Pinkie Pie - Pump: Fast Vibrator: Off - (Unlocks Applejack, Derpy) 
3: Applejack - Pump: Medium Vibrator: Slow - (Unlocks Fluttershy) 
4: Pinkie Pie - Pump: Medium Vibrator: Fast - (Unlocks Rarity) 
5: Rarity - Pump: Fast Vibrator: Fast - (Unlocks None) 
6: Fluttershy - Pump: Fast Vibrator: Fast - (Unlocks Twilight)

NOTE: 5&6 don't matter which order they're in, you just need them both to orgasm. In this order you should have them all in ~2 min