Nothing.
The correct phrase is "on this occasion" and just means "when this is occurring" or "while this is happening." An occasion is just a happening or event.
no
It could be, if occasional is used to mean as an amateur in a profession. The opposite of occasional would be frequent. Other opposites for career could be avocation or hobby.
Assuming you mean 'blueberries' - yes - BUT... only as an occasional treat.
The opposite of occasional is frequent.
Do you mean Mistralton Cave? There are Joltik, Ferroseed, Klink, and the occasional Drilbur and Tyamno.
She wants you to ask her out.
Money you spend from time to time. For example: fixing the roof on your house.
An Occasional Dream was created in 1969.
Occasional Oratorio was created in 1746.
An Occasional Hell was created in 1993.
The duration of Occasional Wife is 1440.0 seconds.
An Occasional Hell has 256 pages.