to further the connection between spouses
Absolutely, but this valid reason must not be at the expense of the procreative aspect, which alone uniquely invites God as a full partner of your marital union. For example a good dinner has two aspects as well: nutritious and social; it would be fine to enjoy a dinner alone if the companion is unavailable for dinner and thus forego the social aspect; but it would be wrong to go to two separate rooms to eat dinner when the companions can have it together.
oral sex
My studied understanding is that any foreplay designed to increase the enjoyment of the marital union is a good thing as long as the marital act remains a unitive and procreative act as a whole, -- which means, oral sex cannot result in the seed ending up in wrong places, and it cannot be something only one partner enjoys. Of course, a risk of those caveats being violated is substantial with oral sex.
NFP teaches that when abstinence is recommended according to the goals of the couple using NFP, it should be complete abstinence, not just avoidance of regular intercourse.
Thanks for your time and input!