A potty training device comprising: a flexible sheet material having a top portion, a bottom portion, a left edge, a right edge, a front side and a back side; a folding seam positioned on the back side of said flexible sheet material to permit folding of said flexible sheet material about the folding seam such that an angle between the top portion and the bottom portion on the back side decreases, wherein the folding seam extends horizontally between the left edge and right edge of said flexible sheet material and separates the said top portion of said flexible sheet material from the said bottom portion of said flexible sheet material; a plurality of attachment tabs; and a means for attaching said flexible sheet material to the underside of a toilet seat in such a way that after attaching said flexible sheet material to the underside of said toilet seat by said means for attaching, the flexible sheet material hangs entirely beneath the underside of said toilet seat, wherein said means for attaching is located within the top portion of said flexible sheet material, and further wherein said bottom portion of said flexible sheet material, when folded about said folding seam, can be positioned to block an opening formed between the toilet seat and a toilet bowl to which said toilet seat is attached, and wherein a surface of said front side of said bottom portion serves as a urine-deflecting surface to deflect a urine stream directed towards said opening into the toilet bowl, wherein in the attached position the front side is the side of the device to which a urine stream makes direct contact, wherein the back side is the side that does not make direct contact with a urine stream, wherein said means for attaching said flexible sheet material to the underside of a toilet seat comprises an adhesive material applied to the plurality of attachment tabs, characterized in that the adhesive material is applied on the front side of the sheet material whereas the folding seam is positioned on the back side of the potty training device and is oriented horizontally across the width of the device, a flexible sheet material having a top portion, a bottom portion, a left edge, a right edge, a front side and a back side; a folding seam positioned on the back side of said flexible sheet material to permit folding of said flexible sheet material about the folding seam such that an angle between the top portion and the bottom portion on the back side decreases, wherein the folding seam extends horizontally between the left edge and right edge of said flexible sheet material and separates the said top portion of said flexible sheet material from the said bottom portion of said flexible sheet material; a plurality of attachment tabs; and a means for attaching said flexible sheet material to the underside of a toilet seat in such a way that after attaching said flexible sheet material to the underside of said toilet seat by said means for attaching, the flexible sheet material hangs entirely beneath the underside of said toilet seat, wherein said means for attaching is located within the top portion of said flexible sheet material, and further wherein said bottom portion of said flexible sheet material, when folded about said folding seam, can be positioned to block an opening formed between the toilet seat and a toilet bowl to which said toilet seat is attached, and wherein a surface of said front side of said bottom portion serves as a urine-deflecting surface to deflect a urine stream directed towards said opening into the toilet bowl, wherein in the attached position the front side is the side of the device to which a urine stream makes direct contact, wherein the back side is the side that does not make direct contact with a urine stream, wherein said means for attaching said flexible sheet material to the underside of a toilet seat comprises an adhesive material applied to the plurality of attachment tabs, characterized in that the adhesive material is applied on the front side of the sheet material whereas the folding seam is positioned on the back side of the potty training device and is oriented horizontally across the width of the device,