If you've been browsing the achievement list you've no doubt noticed these ones:
Not There! - Watched reactions for 5 characters in the Dressing Room.
Quit it! - Watched reactions for 10 characters in the Dressing Room.

Your first thought was probably the same as mine; with the Go Easy achievement just needing you to 'interact' with one of the characters, you just need to do it for 5 and 10 unique ones, right? But with these two, they're actually asking you to watch certain 'special' reactions, instead of just touching them like you've probably been getting carried away with doing.

Each character has one of these unique reactions each, and they fall under one of three categories: Grope, Touch, and Zoom.

They're fairly self-explanatory. Grope requires you to use the grope control on a certain part, Touch requires you to use the touch control on a certain part, and Zoom just needs you to zoom the camera in on a certain part. The thing is, you're not really given any kind of hints as to what these reactions are, especially the zoom ones. Fortunately, this guide will list (hopefully) all of the correct reaction triggers.

Quick word of warning: Any controls I mention will be the Xbox defaults, if you're using a different controller or are trying to play this with a keyboard and mouse, it'll be on you to translate them to your control scheme.

Move either the left or right hand over the area then double tap LT or RT.

• Yumi - Back of the neck
  
• Yozakura - Back of her left arm, just above the elbow
  
• Asuka - Between her chest
  
• Ikaruga - Back of the neck
  
• Hibari - Butt
  
• Ayame - Head
  
• Murasaki - Chest
  
• Homura - Stomach
  
• Yomi - Back of the neck
  
• Hanabi - Stomach
  
• Jasmine - Back
  
• Ryōki - Back of the neck
  
• Leo - Back of the neck

Move the left or right hands over the area and click the left or right thumbstick buttons.

• Shiki - Back
  
• Minori - Head
  
• Katsuragi - Left buttcheek
  
• Yagyū - Stomach
  
• Ryōbi - Both buttcheeks at the same time
  
• Hikage - Stomach
  
• Haruka - Both buttcheeks at the same time
  
• Naraku - Head
  
• Renka - Left buttcheek
  
• Daidōji - Stomach
  
• Yūyaki - Head

Zoom the camera all the way in on the desired area, then simply wait for about 5 seconds.

• Murakumo - Face
  
• Miyabi - Groin
  
• Imu - Face
  
• Ryōna - Chest
  
• Mirai - Face
  
• Kagura - Face
  
• Kafuru - Chest
  
• Rin - Face
  
• Sōji - Face

And that about sums it up. I've skipped the DLC characters because I don't have them so I'm not sure if they have any unique reactions.

This is usually the part where I'd thank you for reading or something, but that's overdone.

So here's a smooch from Ryōna instead.