If a person has no desire to assert themselves onto the environment or to influence it or interact with it at all, but has a strong desire to spend time with and collect energy from other people, what the heck are going to do with that energy when they get it? It just doesn't seem very plausible for that to be a realistic situation for an extrovert. It sounds more like an introvert that is collecting mental stimulation from others through their auxiliary function so they can sit there and digest it with their dominant function. (That is, of course, assuming that it's a preferred thing for the person and not something they only do sometimes. Any person could do anything sometimes.)
I'm usually reserved at first when I'm with new people. However, I expect to become more outgoing as I get to know them. I just accept it as part of the process. If I wasn't planning on becoming more outgoing with them eventually, or if I just wasn't capable of it, I don't see why I'd still want to be with them consistently. I don't feel a magical sense of happiness just by being around other people. It can be fun to just observe sometimes, but overall, I'm more likely to want to do something, or I may just ignore them completely if I just want to think.
The funny thing is that reserved people are still capable of talking a lot. Through talking, I often become less and less reserved as I go. And I do not usually feel awkward at all. I handle myself well, but I know that I'm not fully putting myself out there out at first. Of course, being reserved, I don't go around and try to force myself to talk to everybody just to get it over with. It all happens when it happens. Whatever feels right. I'm easy to talk to, but probably not so easy to actually "connect" with.
If I think it's worth it, I will work at the appropriate rate to rid myself of my reservations so I can enjoy true and stimulating interaction. With some people, this process has taken years, with others, only 30 seconds.