Multivariate kernel density estimations have received much spate of interest. In addition to conventional methods of (non-)classical associated-kernels for (un)bounded densities and bandwidth selections, the multiple extended-beta kernel (MEBK) estimators with Bayesian adaptive bandwidths are invested to gain a deeper and better insight into the estimation of multivariate density functions. Being unimodal, the univariate extended-beta smoother has an adaptable compact support which is suitable for each dataset, always limited. The support of the density MBEK estimator can be known or estimated by extreme values. Thus, asymptotical properties for the (non-)normalized estimators are established. Explicit and general choices of bandwidths using the flexible Bayesian adaptive method are provided. Behavioural analyses, specifically undertaken on the sensitive edges of the estimator support, are studied and compared to Gaussian and gamma kernel estimators. Finally, simulation studies and three applications on original and usual real-data sets of the proposed method yielded very interesting advantages with respect to its flexibility as well as its universality.