Unreliable Delivery, Ratcheting, and Secret Reuse?

[Cy]

If I have a shared secret ratchet going on, and I send something encrypted with 
secret 1,
I can't get rid of secret 1, can I? I need to wait until the peer sends me 
something
encrypted with secret 2, before I know we've both gone past secret 1. But 
waiting
is dumb. If I want to send multiple messages in a row, can't I continue using 
secret 1?
Usually I'll just wait for a reply, but just if there are like, updates or 
typoes, or
something. 

I can't think of a scenario where I'd send a message, and then send another
one, and the first would be more incriminating than the second. Worst comes to 
worst I
could have a special "Abort" message that says I threw away all secrets because 
I sent a
message I regret. But if the Abort message itself is lost and never delivered...

Sorry this is really confusing me. Because if I send S1(M1) then discard S1 for 
S2, with
unreliable delivery, S1(M1) might never reach you, so when you wanted to send 
me a
message you'd use S1 too, and I wouldn't be able to decrypt it anymore. But if 
I hold
onto S1, and only discard it when you use S2 or S3, then we won't have to 
re-establish
the conversation, in a way that seems much easier to monitor than the reuse of 
a shared
secret.