Here is something from the EWTN files:
Anything that constitutes foreplay, that is,
that objectively aims beyond itself to fulfillment in marital intercourse, is not appropriate outside of marriage.
I guess this priest from EWTN is suggesting that foreplay objectively aims beyond itself to fulfillment in marital intercourse. Link:
ewtn.com/vexperts/showresult.asp?RecNum=309094&Forums=0&Experts=0&Days=2002&Author=&pgnu=1&groupnum=0&record_bookmark=4&ORDER_BY_TXT=ORDER+BY+ReplyDate+DESC&start_at
Definition of foreplay:
erotic stimulation preceding sexual intercourse
Merriam-Webster’s Medical Dictionary, © 2002 Merriam-Webster, Inc.
Following these definitions, it seems like something you do a day before without planning to have intercourse would not be considered foreplay for the future marital act. Its like (bear with me, I like making analogies, but they usually turn out lame) if you have a party on Friday night, you don’t put on your makeup and get all dressed Thursday morning. You can buy the clothes beforehand, you can get a haircut etc, but you wouldn’t do the things you do to get dressed for the party until Friday.
ETA: I thought of another analogy (not saying its any better) when you heat up a car before you are going to drive it, you let it idle right before you go drive it, not the week before, not the day before, but right before, since you are prepping it for the drive.