Container or vessel having an anti-splash device and an anti-splash device for a container or a vessel

A drinking vessel comprising:

• a tumbler having an inner surface dimension value;
• a first portion, including
• a proximal surface having a first-dimension value,
• a first rim coupled to the proximal surface and having a second-dimension value, the first-dimension value being larger than the second-dimension value;
• and
• a second portion configured to receive the first portion in a nested relationship, the second portion including
• a collar having an outer dimension value substantially similar to the first-dimension value and an inner dimension value substantially similar to the second-dimension value;
• a second rim connected to the collar and having an outer dimension value substantially similar to the second-dimension value and the inner surface dimension value;
• a baffle at least partially in contact with the collar at an edge of the baffle and at least partially surrounded by the collar, wherein the baffle defines a first through-hole at a central region of the baffle and a second through-hole at the edge of the baffle;
• and
• a flap connected to the baffle at the second through-hole, the flap configured to at least partially impede fluid flow through the second through-hole;
• wherein the flap is connected at a connection point to the baffle at a first angle defined by the connection point as a first vertex, the edge of the baffle, and the flap;
• wherein the first angle is smaller than a second angle that is defined by the connection point as a second vertex, the edge of the baffle, and a proximal rim of the second portion.