How to Navigate Sensitive Partner

How to navigate a relationship with a sensitive partner? 

For context: I (32f) and my boyfriend (34m) have been dating for 3 months. He disclosed to me early on in the relationship that he is sensitive. Which I like in general. I like that he has empathy because that is the grounds for a lot of our shared beliefs. He is the man of my dreams and I have no other issues with him besides this. 

Skip the next two paragraphs if you don't want to read about the specific situations.

However, a couple things happened over the weekend that made us want to reconsider how we approach this. The first instance is when he invited his sister over to my house for their annual summerween holiday. You basically watch a spooky movie, carve out watermelons to make Jack o'melons, eat candy, and finish the night with an episode from Gravity Falls titled Summerween. I do live with my mom and she came home late from work. He felt embarrassed about watching a cartoon in front of her and expressed that to me. I tried to reassure him that my mom wouldn't care that we're adults in our thirties watching a cartoon. I really didn't want him to feel uncomfortable in my home, I also don't really care about my mom's opinion. But I understand that he might. Well I thought I was trying to be reassuring, but he thought I was pushy and later expressed that he got a little upset about it. We talked it out and clarified my position on the situation and he ended up being fine.

The next day, we decided to watch Hereditary in the early afternoon. He's already seen it before and i generally don't watch horror. I'll admit it's one of the scariest movies I've seen. To cope with scary movies I tend to incorporate them into jokes or play so that they become less serious. He however does not joke about that kind of stuff at all. But when he told me about that he specifically mentioned pranking or trying to scare him (like hiding in a corner to jump out at him type of stuff). Couple hours after watching the movie we were playing around and joking with each other. I was tickling him so he ran into my bathroom and tried to close the door, so I started knocking on it. If you have watched the movie you would know that one of the characters bangs her head against the attic door really fast in a supernatural way. He got that I was referring to the movie and got upset that I was joking about it. He thought I was trying to scare him because he was in my bathroom alone. But I had to clarify my position again and tell him that we were laughing and playing and I thought it was just a way to make the movie less serious. I also wasn't trying to scare him, which I thought was what he meant when he said he doesn't play like that with scary movies. In hindsight though I can understand how it would have been scary in his position.

We talked some more and he admitted that he was a little sensitive. But the problem is I like that he's sensitive. He recommended that I tactfully tell him when I feel like he is being overly sensitive. But I feel like there is no tactful way to go about that with a sensitive person. I recommended we perhaps ask clarifying questions instead of jumping straight to conclusions. For example he could have asked what I intended with the knocking. I know that impact is sometimes greater than intention, and I want to be mindful of the things I do that could upset him. But he also says he doesn't want me to walk on eggshells around him.

TLDR: My boyfriend knows he's sensitive and I know i need to make adjustments. But he asks that I try to tell him when he's being overly sensitive, I just don't know how to do that. 

Help.