WTF are these blue-legs doing?

[Jrsydevi1]

For 2 days now one of my blue-leg hermits has been attracting the attention of the other hermits in a way that I have not witnessed before..

One hermit is locked on the other's shell, opening to opening, but doesn't seem to be trying to harm it... indeed, the (seeming) agressor's shell is larger than the (victim's ?)...
They just sit there seemingly doing nothing for 2 days now, locked together...\
From time to time, one or even two other hermits try to horn in on the action, only to be frustrated...

So what's up?.. Do I have a hermit crab sex marathon occurring in my reef?

 

[llowwelll]

Mine do the same thing and I have no idea. I assumed it was they were just eating off the shell of the other.

 

[davelin315]

They're fighting for shells. They won't know whose shell is better until they try it. One will probably be killed off.