YOU SAID:

I rub myself on a watermelon for pleasure

INTO JAPANESE

私は喜びのためにスイカに自分自身をこする

BACK INTO ENGLISH

I rub myself to watermelon for pleasure

INTO JAPANESE

私は喜びのためにスイカに自分自身をこすります

BACK INTO ENGLISH

I rub myself to watermelon for pleasure