'BLF ORPV ERHXRW'
'DV ZOO ORPV ERHXRW'
'R ORPV ERHXRWH GLL UIRVMW'
OK, so, by assumption 'ERHXRW' is 'VISCID'. 'ORPV' is '_ I _ _', not a lot to go on yet. 'UIRVMW' is '_ _ I _ _ D'.
The last message gives us something a little more promising to work with.
'I (something) VISCIDS (something) (something).' 'ZOO' and 'GLL' are promising, in that they're three letter words with doubled letters. A quick review suggests our best candidates for those are 'ALL', 'SEE', 'OFF', 'TOO', 'ADD', and 'GOO'. We can safely dismiss 'SEE', as we already have the letter that ciphers for S. That gives 'L', 'F', 'D', and 'O' as good candidates for the first letter of 'ORPV'. Assuming for a moment our substitution cipher has no letter substituting for itself, that means 'ORPV' is most likely 'LI _ _', 'FI _ _', or 'DI _ _'. I'm going to assume for a moment 'LIKE' and see how far that can take me.
Our last message becomes... 'I LIKE VISCIDS (_ _ _) (_ _ IE _ D)'... and that last word *could* be 'SHIELD', except that we already know S, and I'm wracking my mind for what else it could be. For now I'm going to wait on an extra text sample.