Pineapples are very acidic which neutralizes the alkalinity of semen, leaving only the sweetness hence why cum tastes sweet after consuming pineapple (not that I have tried tasting my own cum). Would be great if you're glazing women's donuts for fun but if you're trying for a baby better lay off acidic fruit juices. Semen is alkaline to counteract the acidity of vaginal walls and protect sperm cells while it's making its way up to the fallopian tubes. Having a neutral pH semen might kill the sperm once it's injected through CIP.