I spray in my sewing room on my cutting table and spray it in sections with the windows open and the ceiling fan on gentle to force the air down. Two things I have learned, 1.) spray the batting, not the quilt. Once I used Sullivan's basting spray to adhere stabilizer for embroidery and it actually turned yellow on the white fabric and did not wash out. (I was very upset.) And the second item, get or make a mask to wear while spraying. There is a bit of over-spray and can be very irritating to one's nose. I use the paper masks people use to mow lawns - have found them at the Home Depot and also at the Dollar Tree.
There has been no trouble with any of my sewing machines. After spraying them I do usually wait a bit but that is more because of the smell because it takes little time to dry. (But I live in So. Cal. where the weather is very dry.)
Hope all goes well.