What does it mean when a guy rests his head on your shoulder?

So this guy is my crush and yesterday when we were home at my friends house, we were 6 people (we are all 15 years old). And me and my crush was next to each others all the time like sat next to each others on the couch and he teased me a lot but it was funny and cute. Then at like 11pm-12pm he was first next to me at the couch and then he came closer and closer and then he randomly rested his head on my shoulder the whole night and we took pictures together and we were so close next to each others, it was so cute and amazing. I don't know thought what it means, why did he rest his on my shoulder etc, what does it mean?
What does it mean when a guy rests his head on your shoulder?
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