Everybody likes something different so it may take some experimenting. I really enjoy the feeling of a belly-full of warm soapy water and the demand-defer urges to let it all out. Try some Ivory or Dr. Bronner's soap or maybe some glycerine soap if you think you might enjoy that and use very warm, not quite hot, water (again check the temp with a thermometer until you get a feel for the temps). After filling up, I like to lie on my back and massage my sides and lower abdomen which really gets the urges going. Your SO might be happy to help with this part and perhaps massage other areas as well. 😉 Also have him take his time in getting you good and lubricated, inside and out, before inserting the nozzle. If you're interested in anal sex, that will only help things along and should feel good.
One thing I've noticed is that it seems impossible to experience more than one intense sensation at one time so if I engage in, um, erotic massage, the cramping/urgency seems to lessen or go away entirely. Often I'll go back and forth several times alternately experiencing the urges to go and the urges to come. 😄
If there's a particular story or two that really get you hot, you could try enacting it with your husband or alone. The mind is the largest sex organ we have afterall.
I wouldn't recommend it right away, but if you think extreme urgency might be your thing, you could try the infamous Milk & Molasses enema. It's easy to take and impossible to hold once it starts working. I'm pretty sure it was an M&M that first got me hooked on enemas and the feelings of urgency when I was given one as a young child. Be VERY near a toilet however. People's reactions vary, but for me once it kicks in, rather than the usual demand/defer cycle, the demand just gets more and more intense the longer I try to hold it.
Good luck and don't give up on experimenting; anything new takes time to work out.