You people do realize there was no gender specific title when she told her about her "internet friend" so for all you know it is a woman. If she really wanted it to head in the direction of "fuck a random dude" Saburouta would have just wrote male specifics rather than keep it so anonymous (taking into account raws also didn't have gender specifics).
That or I'm reaaaaaalllly wishfully thinking.
Either way, I really want to know how Mei will deal with Matsuri after she finds all this out because I guarantee she can't possible not find out about it.
I don't think there will be some random dude reveal in this type of manga. It just seems so unlikely, especially since it's in Yuri Hime.