It's pretty much been covered.
- Hard Limit - No to forcing. No to insisting. No to punishing.
- Soft Limit - Work up to it. Communicate the concerns. Practice practice practice. Corn starch and water to make a goop for dealing with texture issues. You can figure out what to flavor it with to deal with flavor issues. A med-test if you're concerned with health issues.
- Not in the Mood - It depends on the nature of the relationship, but discipline of some sort seems appropriate. It would be within my relationship.