"I mean I can do it when I'm very relaxed, and with good friends, then I think I can be amusing"

Rowan Atkinson is suggesting that he can be amusing when he is in a relaxed and comfortable environment. He implies that he is more likely to be funny when he is surrounded by good friends. This suggests that he is more confident in his ability to be humorous when he is in a familiar and comfortable setting. He is implying that he is more likely to be successful in making people laugh when he is in a relaxed and familiar environment. This could be interpreted as him being more comfortable in his own skin and being able to express himself more freely when he is surrounded by people he knows and trusts. It could also be interpreted as him being more confident in his ability to make people laugh when he is in a relaxed and comfortable setting.