A retaining holster, comprising: a rim end; a leak-proof opposing bottom end; a reservoir, therebetween, for containing drippings of biological fluids from a suction tube; and a recessed lid, comprising: coupling, a peripheral edge of which overlaps the rim end of the retaining holster, such that the rim end is covered by the peripheral portion, resulting in the rim end and peripheral portion fitting into groove; a recessed portion, having a length L 1; a fixed displacement retaining disk, peripherally coupled to a distal suction end of the recessed portion, such that L 1 determines a length separating rim end from a top surface of the retaining disk, comprising: slits that radiate from a center, wherein the slits divide the retaining disk into a plurality of flexible arcuate flaps, and wherein at least one of the plurality of flexible arcuate flaps flex toward the bottom end when a suction end of the suction tube contacts the plurality of flexible arcuate flaps during insertion of said suction end of the suction tube into the hollow cavity, forming a central aperture through the center of the recessed lid, said flexible arcuate flaps and central aperture of said recessed lid being operative in combination with said suction tube as a splash guard for preventing the biological fluids from being ejected from a reservoir of the hollow cavity that is between the recessed lid and the bottom end and for releasably retaining said suction end of the suction tube in the reservoir after insertion of said suction end through the central aperture. a rim end; a leak-proof opposing bottom end; a reservoir, therebetween, for containing drippings of biological fluids from a suction tube; and a recessed lid, comprising: coupling, a peripheral edge of which overlaps the rim end of the retaining holster, such that the rim end is covered by the peripheral portion, resulting in the rim end and peripheral portion fitting into groove; a recessed portion, having a length L 1; a fixed displacement retaining disk, peripherally coupled to a distal suction end of the recessed portion, such that L 1 determines a length separating rim end from a top surface of the retaining disk, comprising: slits that radiate from a center, wherein the slits divide the retaining disk into a plurality of flexible arcuate flaps, and wherein at least one of the plurality of flexible arcuate flaps flex toward the bottom end when a suction end of the suction tube contacts the plurality of flexible arcuate flaps during insertion of said suction end of the suction tube into the hollow cavity, forming a central aperture through the center of the recessed lid, said flexible arcuate flaps and central aperture of said recessed lid being operative in combination with said suction tube as a splash guard for preventing the biological fluids from being ejected from a reservoir of the hollow cavity that is between the recessed lid and the bottom end and for releasably retaining said suction end of the suction tube in the reservoir after insertion of said suction end through the central aperture. coupling, a peripheral edge of which overlaps the rim end of the retaining holster, such that the rim end is covered by the peripheral portion, resulting in the rim end and peripheral portion fitting into groove; a recessed portion, having a length L 1; a fixed displacement retaining disk, peripherally coupled to a distal suction end of the recessed portion, such that L 1 determines a length separating rim end from a top surface of the retaining disk, comprising: slits that radiate from a center, wherein the slits divide the retaining disk into a plurality of flexible arcuate flaps, and wherein at least one of the plurality of flexible arcuate flaps flex toward the bottom end when a suction end of the suction tube contacts the plurality of flexible arcuate flaps during insertion of said suction end of the suction tube into the hollow cavity, forming a central aperture through the center of the recessed lid, said flexible arcuate flaps and central aperture of said recessed lid being operative in combination with said suction tube as a splash guard for preventing the biological fluids from being ejected from a reservoir of the hollow cavity that is between the recessed lid and the bottom end and for releasably retaining said suction end of the suction tube in the reservoir after insertion of said suction end through the central aperture. wherein the slits divide the retaining disk into a plurality of flexible arcuate flaps, and wherein at least one of the plurality of flexible arcuate flaps flex toward the bottom end when a suction end of the suction tube contacts the plurality of flexible arcuate flaps during insertion of said suction end of the suction tube into the hollow cavity, forming a central aperture through the center of the recessed lid, said flexible arcuate flaps and central aperture of said recessed lid being operative in combination with said suction tube as a splash guard for preventing the biological fluids from being ejected from a reservoir of the hollow cavity that is between the recessed lid and the bottom end and for releasably retaining said suction end of the suction tube in the reservoir after insertion of said suction end through the central aperture.