There are many terms from classic and modern SF that remain unresearched, and the Historical Dictionary of Science Fiction will be continually updated, especially as additional resources are put online. Boing Boing is syndicating new entries from the HDSF on a regular basis. (Read the series introduction.)
At the intersection of terms from SF fandom and verbed nouns is the ultimate example: the verb fan itself. The HDSF had already entered the verbal noun fanning, which dates to 1940; now we're putting in the actual verb, which follows closely behind, in 1941. It has been in wide use among fans throughout its entire history. (The noun fan, while extremely common, is not used in any particularly special way in SF, and is thus not itself included.)
We are also adding the verb use of fangirl. The noun fangirl goes back to the 1930s, about fifteen years after fanboy, though in both cases the more modern nuances don't really show up until the 1980s.
There is an interesting example of lack of parallelism in the development of these words: there's no corresponding entry for fanboy as a verb. It is perhaps not surprising that fanboy, which arose in the context of sports fans, would appear before fangirl. But now both terms are in frequent use, and they each have their own connotations beyond merely referring to an (obsessive) fan of a particular gender. Fanboys are typically characterized as aggressive and fiercely protective of their fandom; fangirls are regarded as immature and out of control.
But when used as verbs, fangirl is much more common than fanboy. There's not necessarily a reason for this. It's not purely sexist—fangirl is often used by women describing their own behavior. If anything it may simply be a more useful term; men can fangirl too, whereas there doesn't seem to be as much need to describe the specific behavior of fanboys. But it's on the list, and if it gains more currency, we can add it in the future.