Rail Pass Flexi/Regional Pass

Hello krishvid. You'll find all specifics and explanation at the Swiss Flexi Pass and Regional-Pass Bernese Oberland pages.

The Swiss Flexi Pass offers free traveling on consecutive or non-consecutive days, just how you like it. It's valid from and up to the last free travel day. The maximum validity is one month (so the last free travel day can't be later than a month from the first free travel day), but you can also decide to use the free travel days within a shorter period or on consecutive days. On remaining days in between the first and last free travel day, a 50% discount applies.

Yes, the free travel days offered by the Regional-Pass Bernese Oberland (I assume that's the one you mean?) can be used consecutively.