I didnt read all of the replies...
BUT PLAY. PLAY, enjoy yourself. If he lays in your closed guard OPEN it, play some random inverted guard, invent one - have fun and challenge yourself. It is training.
This allows your partner to come out of his shell. If you get subbed, smile, and keep going. You know you're playing and trying new things, if he feels awesome about it, dont worry.
BUT PLAY. PLAY, enjoy yourself. If he lays in your closed guard OPEN it, play some random inverted guard, invent one - have fun and challenge yourself. It is training.
This allows your partner to come out of his shell. If you get subbed, smile, and keep going. You know you're playing and trying new things, if he feels awesome about it, dont worry.