Re: Cum on in.
If you look at the dictionary definition of the word - “cum” - is a preposition and its use as iftar-cum-dinner is perfectly correct. The meaning of “cum” that you guys are so focused on is just a vulgar slang.
Another example is “the doctor had to prick the patient’s finger to draw a blood sample”. This sentence shows that the word “prick” is not a vulgar word, rather its slang use is. People who use “cum” as a replacement for “come” may be lazy, but using “cum” to denote semen is much more vulgar than using it for “cum on in”. Lets keep a little perspective here.