If your word needs to end in "es", like "kisses", replace %%mc-plural-s%% with %%mc-plural-es%%, like so: kiss%%mc-plural-es%%
If your plural ends in "ies", as in "replies", replace %%mc-plural-s%% with %%mc-plural-ies%%, like so: repl%%mc-plural-ies%%
The pluralization of "kisses" is great because there is only kiss, and kiss+es. If it does not have multiple responses, then "1 kiss" is displayed. However, in the second example, the example given will show: "2 replies" or "1 repl". I think someone should edit the FAQ to show how to make "1 reply" show if only 1 reply is present.
*just a thought
UPDATE It has come to my attention that %%mc-plural-ies%% will add a "y" if singular. I think this needs to be explained in the FAQ. Also, it does not explain how to make it have something OTHER Then "y" on the end. There was a request recently in support dealing with another language that did not use "y" for singular.