According to my testing, Bliss is not a Switchword.
All Switchwords can be utilized by declaring, affirming, chanting, singing or just mentally intending. Bliss appears to be most effective if said just one time. It appears to be part of a category of elusive words. Elusive words are terms that embody elusive states of being. Bliss is a very high state of joy or elation. It is fleeting. For once attained it begins to fade to simple joy, happiness and/or elation. Bliss feels like the highest form of joy, the best place one can imagine, but when one achieves it, suddenly it is no longer the highest joy, the best place one can imagine. One now can see a higher place. This is why Abraham says "follow your bliss."
When repeating the word Bliss, and focusing on it, one can become lost and disillusioned because there is always a belief that there is state of joy, happiness and elation beyond where one currently is, so one can "tumble" into negative feelings if one is feeling unable to attain and maintain Bliss.
Abraham instructs one to, when in an uncomfortable, negative place, reach for the best feeling one has access to. The goal is to get from a negative emotional state to a positive one. That is Abraham's description of "following your bliss."
To my knowledge Abraham does not tell one to continue trying to reach a more and more positive state once one reaches a positive state. Instead, we are told that once one reaches the positive emotional state one begins to attract more and more positive to oneself, maintaining and increasing the positive state.
Anyway, I hope this makes sense to you. I am just saying what I see when I look into Bliss. It is a good word (of course), but seems to be a bit elusive and when focused on excessively could possibly leave one with a feeling of lack.